Patent Publication Number: US-10780847-B2

Title: Vehicular circuit body

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a continuation of International Application No. PCT/JP17/023313 filed on Jun. 23, 2017, and claims priority from Japanese Patent Applications No. 2016-125287 filed on Jun. 24, 2016, No. 2016-125896 filed on Jun. 24, 2016 and No. 2016-131165 filed on Jun. 30, 2016, the entire contents of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present invention relates to a vehicular circuit body routed in a vehicle. 
     BACKGROUND ART 
     In a vehicle, for example, source power is required to be appropriately supplied to a large number of various electric components from an alternator (generator) or a battery which is a main power source. A system used to supply such source power is also required to have a function of switching between ON and OFF of the supply of power as necessary, or a function of cutting off a current for each system in a case where an excessive current flows through an electric component. 
     In a general vehicle, a wire harness which is an aggregate of a plurality of electric wires is routed on the vehicle, and a main power source is connected to electric components at each location via the wire harness so that power is supplied thereto. Generally, a junction block is used to distribute source power to a plurality of systems, a relay box is used to control ON and OFF of the supply of power for each system, or a fuse box is used to protect each electric wire or a load of the wire harness. 
     The vehicle is provided with a plurality of control units for controlling the electric components, and the control units and the electric components are communicably connected to each other via the wire harness. 
     For example, a wire harness disclosed in Patent Document 1 includes a network transmission path and a circuit for providing power, GND and other signals. The wire harness includes a wire harness trunk line, a sub-wire harness, an optional sub-wire harness, and a network hub device.
         Patent Document 1: JP-A-2005-78962       

     SUMMARY OF INVENTION 
     In recent years, vehicle systems including such a power source system or communication system have become advanced due to an increase in the number of mounted electric components, complexity of control, or the like. An automatic driving technology is rapidly evolving, and safety requirements for various functions are also increasing in order to cope with this automatic driving. 
     Along with this, a structure of a wire harness routed on a vehicle body tends to be complicated. Therefore, for example, as in Patent Document 1, the wire harness having a complex shape as a whole is formed by combining the wire harness trunk line, the sub-wire harness, and the optional sub-wire harness, and thus connection to various electric components disposed at various locations on a vehicle body can be performed. 
     Since a diameter of each electric wire forming the wire harness or the number of electric wires increases due to an increase in the number of electric components mounted on a vehicle, there is a tendency that a size of the entire wire harness increases or a weight thereof increases. The types and the number of components of wire harness to be manufactured increase due to a difference between vehicle models mounted with a wire harness or increases in types of optional electric components mounted on a vehicle, and thus it is difficult to standardize components forming the wire harness, and component cost or manufacturing cost increases. 
     In a work process of manufacturing a wire harness, in order to finish the wire harness in a predetermined routing shape, a bundle of a plurality of electric wires forming the wire harness is pulled around over a long distance along a path which is designated in advance, and thus a lot of work time is required. Since almost all of electric wires are collected at a trunk line portion of the wire harness, the number of bundled electric wires increases, and thus a weight thereof increases. 
     For example, in a case where a new electric component which is not expected at initial design is mounted on a vehicle, a new electric wire is required to be added to a wire harness in order to secure a path along which a special signal is transmitted between the electric component and another electric component or to supply source power thereto. However, a wire harness has a complex structure or shape, and it is very difficult to add other electric wires to the existing wire harness in the future. Therefore, a new wire harness having differing type or component number is required to be designed so as to be manufactured as a separate product. 
     The present invention has been made in consideration of the above-described circumstances, and an object thereof is to provide a vehicular circuit body in which a structure for electrical connection between various electric components and a power source on a vehicle and between the electric components, particularly, a configuration of a trunk line portion is simplified and a new electric wire can be easily added. 
     In order to achieve the above-described object, a vehicular circuit body according to the present invention is characterized in terms of the following (1) to (7). 
     (1) A vehicular circuit body provided in a vehicle, including: 
     a trunk line that extends in at least a front-and-rear direction of the vehicle; and 
     a plurality of control boxes that are provided in the trunk line, 
     wherein each of the plurality of control boxes is able to connect with a branch line that is directly or indirectly connected to an accessory, and 
     wherein the trunk line includes a power source line having a predetermined current capacity and a communication line having a predetermined communication capacity. 
     (2) The vehicular circuit body according to (1), 
     wherein the trunk line includes power source lines of two systems. 
     (3) The vehicular circuit body according to (1), 
     wherein the branch line includes a power source line and a communication line, 
     wherein each of the plurality of control boxes includes a branch line connection portion to which the branch line is connected, and a branch line control unit that distributes power from the trunk line to the branch line by controlling the branch line connection portion according to a control program, and 
     wherein the control program can be externally changed according to the accessory connected to the branch line. 
     (4) The vehicular circuit body according to (1), 
     wherein the communication line of the trunk line is routed so that the plurality of control boxes are connected in a ring form. 
     (5) The vehicular circuit body according to (1), 
     wherein the branch line includes a power source line and a communication line, 
     wherein each of the plurality of control boxes includes a plurality of branch line connection portions to and from which the communication line of the branch line is attachable and detachable, and wherein each of the plurality of branch line connection portions is provided with a lock function portion that is physically or electrically brought into a lock state in a case where the branch line is not connected thereto. 
     (6) The vehicular circuit body according to (1), 
     wherein the branch line includes a power source line and a communication line, 
     wherein the vehicle is divided into a plurality of regions, 
     wherein at least two control boxes are disposed in the regions which are different from each other, each of which includes a gateway conversing communication methods for the communication line of the branch line and the communication line of the trunk line, and 
     wherein a plurality of the gateways are able to communicate with each other via the communication line of the trunk line. 
     (7) The vehicular circuit body according to (1), wherein the branch line includes at least one of a power source line and a communication line, 
     wherein the communication line of the trunk line has a transmission path for an optical signal, and 
     wherein the communication line of the branch line has a transmission path for an electric signal. 
     With the configuration of (1), it is possible to provide a vehicular circuit body in which a configuration of the trunk line portion is simplified and a new electric wire can be easily added. 
     With the configuration of (2), since the power source lines of two systems are formed between the control boxes, one power source line is used for backup so as to reduce a probability that the supply of power may be stopped, or power can be stably supplied by increasing a voltage of one system as necessary. 
     With the configuration of (3), appropriate power can be supplied to the accessory via the branch line from the trunk line by changing the control program regardless of the kind of accessory connected to the branch line. 
     With the configuration of (4), even if a failure occurs in any communication line connecting the plurality of control boxes to each other, communication can be continuously performed by using a route in a direction opposite to a location where the failure occurs. Therefore, it is possible to improve the reliability of communication on the trunk line of the vehicular circuit body. 
     With the configuration of (5), even if branch line connection portions of the number larger than the number of connected branch lines at the present time are provided in the control box so that branch lines can be additionally connected in the future, it is possible to prevent a branch line which should not be connected from being connected to a branch line connection portion to which no branch line is connected. Therefore, for example, it is possible to prevent a program rewriting device from being connected to a branch line connection portion to which no branch line is connected for the purpose of rewriting a program of a control unit of a control box with malice. 
     With the configuration of (6), since the gateway conversing communication methods for the communication line of the trunk line and the communication line of the branch line is provided in each region of the vehicle, an accessory provided in a region is connected to a control box provided in the region via the branch line, and thus transmission and reception of signals can be performed between the accessory and the trunk line. 
     With the configuration of (7), since the trunk line connecting the control boxes to each other has the transmission path for an optical signal, it is possible to increase a transmission capacity between the control boxes. Since an optical signal is used, it is hardly influenced by electromagnetic noise generated in the power source line of the trunk line or external apparatuses, and thus it is possible to increase reliability of communication. 
     It is possible to provide a vehicular circuit body in which a configuration of a trunk line portion is simplified and a new electric wire can be easily added. 
     As mentioned above, the present invention has been described briefly. Details of the present invention will become more apparent by reading through modes for carrying out the invention (hereinafter, referred to as “embodiments”) described below with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view illustrating a configuration example of principal portions of an on-vehicle device including a vehicular circuit body in an embodiment of the present invention. 
         FIG. 2  is a block diagram illustrating a configuration example of an on-vehicle system. 
         FIGS. 3A and 3B  are electrical circuit diagrams illustrating configuration examples of backbone trunk lines. 
         FIG. 4  is a block diagram illustrating a configuration example of an electrical circuit inside a control box. 
         FIG. 5  is a block diagram illustrating a configuration example of functions of the control box. 
         FIG. 6  is a block diagram illustrating a configuration example of a communication system in an on-vehicle system. 
         FIG. 7  is a block diagram illustrating a configuration example of the communication system in the on-vehicle system including a gateway. 
         FIGS. 8A, 8B and 8C  are perspective views respectively illustrating configuration examples for physically protecting unused connectors in a connection portion of the control box. 
         FIG. 9  is a flowchart illustrating an example of a process for protecting an unused connector through control. 
         FIG. 10  is a block diagram illustrating a configuration example of a communication system inside the control box. 
         FIG. 11  is an electrical circuit diagram illustrating a circuit configuration example for supplying power to each communication system inside the control box. 
         FIG. 12  is an exploded view illustrating a configuration example of a wire harness obtained by combining a printed circuit board with electric wires. 
         FIG. 13  is a perspective view illustrating an example of an exterior of a control box having USB ports. 
         FIGS. 14A, 14B and 14C  are plan views illustrating three configuration examples of circuit boards built in a control box or the like. 
         FIG. 15  is a perspective view illustrating a configuration example of a connection location of a routing member forming a trunk line. 
         FIG. 16  is a plan view illustrating a connection example between a control box on the trunk line and branch line sub-harnesses. 
         FIG. 17  is a plan view illustrating a connection example between a control box on the trunk line and branch line sub-harnesses. 
         FIGS. 18A and 18B  are plan views illustrating connection examples between a trunk line and branch line sub-harnesses. 
         FIG. 19  is a perspective view illustrating a connection example between a control box on the trunk line and branch line sub-harnesses. 
         FIG. 20  is a perspective view illustrating an arrangement example of a trunk line and a plurality of branch line sub-harnesses routed on a vehicle body. 
         FIGS. 21A and 21B  are block diagrams illustrating a plurality of control boxes and a communication trunk line connecting the control boxes to each other. 
         FIG. 22  is an electrical circuit diagram illustrating a configuration example of a control box having a recovery function. 
         FIGS. 23A and 23B  are block diagrams illustrating connection examples between a wire harness and a load. 
         FIG. 24  is a perspective view illustrating a specific example of arrangement and connection of various constituent elements on a vehicle body. 
         FIGS. 25A, 25B and 25C  are block diagrams illustrating specific examples of connection states of a trunk line, a control box, a battery, and the like. 
         FIGS. 26A, 26B, 26C, 26D and 26E  are block diagrams illustrating specific examples of connection states of a trunk line and one or more batteries. 
         FIG. 27  is a block diagram illustrating a specific example of a connection state of a trunk line and a plurality of batteries. 
         FIG. 28  is an electrical circuit diagram illustrating a configuration example of a power source system in an on-vehicle system. 
         FIG. 29A  is a block diagram illustrating a configuration example of an on-vehicle system, and FIG.  29 B is a perspective view illustrating an example of an exterior of the same on-vehicle system. 
         FIGS. 30A and 30B  are longitudinal sectional views respectively illustrating configuration examples of different backbone trunk lines. 
         FIG. 31  is a time chart illustrating an example of a correspondence relationship between a power source current and a power source voltage in a case where special power source control is performed. 
         FIGS. 32A, 32B and 32C  are longitudinal sectional views respectively illustrating configuration examples of different backbone trunk lines. 
         FIG. 33  is an electrical circuit diagram illustrating a configuration example of a power source system in an on-vehicle system. 
         FIG. 34  is a longitudinal sectional view illustrating a configuration example of a communication cable. 
         FIG. 35  is a block diagram illustrating a configuration example of a communication system in an on-vehicle system. 
         FIG. 36  is a block diagram illustrating a configuration example of communication systems in an on-vehicle system in which the communication systems are connected in a ring form. 
         FIG. 37  is a block diagram illustrating a configuration example of communication systems in an on-vehicle system in which the communication systems are connected in a star form. 
         FIGS. 38A, 38B and 38C  illustrate communication connection states between apparatuses in different situations, in which  FIG. 38A  is a perspective view, and  FIGS. 38B and 38C  are block diagrams. 
         FIG. 39  is an electrical circuit diagram illustrating a configuration example of a power source system in an on-vehicle system. 
         FIG. 40  is an electrical circuit diagram illustrating a configuration example of a power source system in an on-vehicle system. 
         FIG. 41  is an electrical circuit diagram illustrating a configuration example of a backup power source circuit. 
         FIG. 42  is an electrical circuit diagram illustrating a configuration example of a power source circuit for power load. 
         FIG. 43  is a block diagram illustrating a configuration example of an on-vehicle system. 
         FIG. 44  is a block diagram illustrating a configuration example of a control box which can switch between a plurality of communication protocols. 
         FIG. 45  is a block diagram illustrating a configuration example of a control box. 
         FIGS. 46A and 46B  are block diagrams illustrating a configuration example of an on-vehicle system. 
         FIG. 47  is a block diagram illustrating a configuration example of a circuit module provided in a driver seat door panel. 
         FIG. 48  is a block diagram illustrating a configuration example of a circuit module provided in a passenger seat door panel. 
         FIG. 49  is a block diagram illustrating a configuration example of a circuit module provided in a rear seat door panel. 
         FIG. 50  is a block diagram illustrating a configuration example of a circuit module provided in a vehicle&#39;s roof. 
         FIG. 51  is a block diagram illustrating a configuration example of a smart connection connector. 
         FIGS. 52A and 52B  are block diagrams respectively illustrating configuration examples of communication systems in different on-vehicle systems. 
         FIG. 53  is a block diagram illustrating a configuration example of a communication system in an on-vehicle system. 
         FIG. 54  is a block diagram illustrating a configuration example of a communication system in an on-vehicle system. 
         FIG. 55  is a longitudinal sectional view illustrating a configuration example of a communication trunk line BB_LC. 
         FIG. 56  is a time chart illustrating a configuration example of an optical signal on which wavelength multiplexing and time division multiplexing are performed. 
         FIG. 57  is a block diagram illustrating a configuration example of a communication system in an on-vehicle system performing optical multiplexing communication. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Specific embodiments regarding the present invention will be described with reference to the respective drawings. 
     &lt;Disclosure of the Present Invention and Latent Claims&gt; 
     [Power Source- 1 ] 
     In a vehicle, for example, it is necessary to cope with an automatic driving technology, and thus it is necessary to improve reliability of a power source system of a wire harness. For example, even during vehicle crash due to traffic accident, it is preferable that the supply of power to an important on-vehicle apparatus is not stopped, and a problem can be solved by only the vehicle itself. In a vehicular circuit body such as a wire harness, there is the need for reducing component cost or manufacturing cost by simplifying the configuration, or reducing the number of components by using a component in common to various kinds of vehicles. Therefore, the vehicular circuit body is configured as described in the following (1) to (7). 
     (1) A vehicular circuit body provided in a vehicle, includes: 
     a trunk line that extends in at least a front-and-rear direction of the vehicle; and 
     a plurality of control boxes that are provided in the trunk line, 
     in which the trunk line includes power source lines of two systems and a communication line. 
     With this configuration, since the power source lines of two systems are formed between the control boxes, one power source line is used for backup so as to reduce a probability that the supply of power may be stopped, or power can be stably supplied by increasing a voltage of one system as necessary. 
     (2) In the vehicular circuit body according to the above (1), the power source lines of two systems transmit power of the same voltage. 
     With this configuration, the power source lines of two systems can be used together, or one power source line can be used for backup, depending on situations. 
     (3) In the vehicular circuit body according to the above (1), the power source lines of two systems transmit power of different voltages. 
     With this configuration, in a case where a load having large power consumption is connected, a large power source current flows, and thus a voltage drop in a supply line path increases. Thus, it is possible to prevent an increase in a power loss by selecting a higher power source voltage. 
     (4) In the vehicular circuit body according to the above (1) to (3), the plurality of control boxes include a first control box, and a second control box located further toward a downstream side than the first control box with respect to a power source, and in which the first control box transmits power to the second control box by using only one of the power source lines of two systems. 
     With this configuration, one of the power source lines of two systems is secured as a standby power source system, and in a case where abnormality occurs in a power source line in use, switching to the standby power source system can be performed. 
     (5) In the vehicular circuit body according to any one of the above (1) to (4), the vehicle circuit body further includes a branch line that is connected to an accessory provided in the vehicle. 
     With this configuration, it is possible to collectively supply power to the trunk line from a power source, and to distribute the power from the trunk line to each accessory. 
     (6) In the vehicular circuit body according to the above (5), one end of the branch line is connected to the control box. 
     With this configuration, it is possible to distribute power to be supplied to an accessory, from the control box. 
     (7) In the vehicular circuit body according to the above (1) to (6), the power source lines of two systems are provided to extend in parallel. 
     With this configuration, the power source lines of two systems can be disposed together by connecting the control boxes to each other via a single trunk line. 
     [Power Source- 2 ] 
     In vehicles, different numbers or different kinds of electric components (accessories) for each vehicle are connected due to a difference in a vehicle, a difference in a grade, a difference in a destination, and a difference in an optional apparatus. If the number or the kind of electric component is changed, a configuration of a wire harness may be changed. A new kind of electric component which is not expected during design of a vehicle may be added to a vehicle in the future. In this case, preferably, the added electric component can be used by just being connected to an existing wire harness or the like which has already been mounted in the vehicle. It is preferable that a connection position of each electric component can be changed as necessary. It is preferable that the wire harness or the like can be configured by components in common even if the kind of vehicle, or the number or the kind of electric component to be connected is changed. 
     Therefore, the vehicular circuit body is configured as described in the following (1) and (2). 
     (1) A vehicular circuit body provided in a vehicle, includes: 
     a trunk line that extends in at least a front-and-rear direction of the vehicle; 
     a plurality of control boxes that are provided in the trunk line; and 
     a branch line that connects the control box to an accessory. 
     Each of the trunk line and the branch line includes a power source line and a communication line. 
     Each of the plurality of control boxes includes a branch line connection portion connected to a branch line, and a branch line control unit that distributes power from the trunk line to the branch line by controlling the branch line connection portion according to a control program. 
     The control program can be externally changed according to an accessory connected to the branch line. 
     With this configuration, appropriate power can be supplied to an accessory via the branch line from the trunk line by changing the control program regardless of the kind of accessory connected to the branch line. 
     (2) In the vehicular circuit body according to the above (1), the branch line connection portion includes a plurality of connectors connected to ends of the branch lines, and the plurality of connectors have the same shape. 
     With this configuration, a connector to be connected to a branch line is not required to differ depending on an accessory, and thus it is possible to easily increase the number of accessories or to easily change accessories. 
     [Communication- 1 ] 
     In a vehicle, for example, it is necessary to cope with an automatic driving technology, and thus it is necessary to improve reliability of, for example, a communication system of a wire harness. For example, even during vehicle crash due to traffic accident, it is preferable that a communication system used to control an important on-vehicle apparatus can be maintained in a communicable state, and abnormality does not occur in a vehicle control state. In a vehicular circuit body such as a wire harness used as a communication path, there is the need for reducing component cost or manufacturing cost by simplifying the configuration, or reducing the number of components by using a component in common to various kinds of vehicles. 
     Therefore, the vehicular circuit body is configured as described in the following (1). 
     (1) A vehicular circuit body provided in a vehicle, includes: 
     a trunk line that extends in at least a front-and-rear direction of the vehicle; and 
     a plurality of control boxes that are provided in the trunk line. 
     The trunk line includes a power source line and a communication line. 
     The communication line is routed so that the plurality of control boxes are connected in a ring form. 
     With this configuration, even if a failure occurs in any communication line connecting the plurality of control boxes to each other, communication can be continuously performed by using a route in a direction opposite to a location where the failure occurs. Therefore, it is possible to improve the reliability of communication on the trunk line of the vehicular circuit body. 
     [Communication- 2 ] 
     Various electric components may be connected to a wire harness of a vehicle. It is preferable to use a component in common or be able to freely change a connection position of a connector or the like of an electric component. Thus, it may be expected that a communication standard generally used is employed, or a plurality of connectors or the like having a normal shape are prepared on a wire harness of a vehicle. However, for example, from the viewpoint of security, there is a case where some connectors are required not to be freely used by a user of a vehicle or a third party unless special permission is given. However, in a case where a communication method based on a standard is employed, or a connector based on a standard is employed, a user or the like may freely use a connector in an unoccupied state, and thus a problem such as security occurs. 
     Therefore, the vehicular circuit body is configured as described in the following (1) to (5). 
     (1) A vehicular circuit body provided in a vehicle, includes: 
     a plurality of control boxes; 
     a trunk line that connects the plurality of control boxes to each other; and 
     a branch line that directly or indirectly connects a control box to an accessory. 
     Each of the trunk line and the branch line includes a power source line and a communication line. 
     Each of the control boxes includes a plurality of branch line connection portions to and from which the communication line of the branch line is attachable and detachable. 
     The plurality of branch line connection portions are provided with a lock function portion that is physically or electrically brought into a lock state in a case where the branch line is not connected thereto. 
     With this configuration, even if branch line connection portions of the number larger than the number of connected branch lines at the present time are provided in the control box so that branch lines can be additionally connected in the future, it is possible to prevent a branch line which should not be connected from being connected to a branch line connection portion to which no branch line is connected. Therefore, for example, it is possible to prevent a program rewriting device from being connected to a branch line connection portion to which no branch line is connected for the purpose of rewriting a program of a control unit of a control box with malice. 
     (2) In the vehicular circuit body according to the above (1), each of the plurality of branch line connection portions includes a connector to and from which an end of the communication line is attachable and detachable, and in which the lock function portion includes a cover member that collectively covers openings of a plurality of the connectors, and a key part that prevents the cover member from being detached from the connectors in a lock state. 
     With this configuration, in a case where a branch line is not required to be connected to any branch line connection portion at the present time, all connectors of the branch line connection portion are collectively covered by the cover member, and the cover member cannot be detached by the key part. Thus, a branch line can be prevented from being connected to a connector wrongly or with malice. 
     (3) In the vehicular circuit body according to the above (1), each of the plurality of branch line connection portions includes a connector to and from which an end of the communication line is attachable and detachable. The lock function portion includes a cover member that covers at least a part of an opening of any one of the connectors, and a key part that prevents the cover member from being detached from the connector in a lock state. 
     With this configuration, the cover member can be attached only to a necessary connector among the plurality of connectors and not be detached. Therefore, in a case where branch lines are not connected to some connectors among the plurality of connectors, the cover member is attached to the connectors, and thus branch lines can be prevented from being connected to the connectors wrongly or with malice. 
     (4) In the vehicular circuit body according to the above (1), each of the plurality of branch line connection portions includes a connector to and from which an end of the communication line is attachable and detachable, and in which the lock function portion is a seal member which covers an opening of at least one of the connectors, and the seal member includes unsealing display means for identifying unsealing. 
     With this configuration, since the seal member has the unsealing display means, it is possible to prevent a person with malice from connecting a branch line to a connector. In a case where a branch line is illegally connected to a connector, it is easy for a dealer or the like to find out the face. 
     (5) In the vehicular circuit body according to the above (1), each of the plurality of branch line connection portions transmits a signal to a connected target object, and determines whether or not transmission and reception of signals to and from the target object are permitted on the basis of a response to the signal from the target object. 
     With this configuration, even if a branch line which should not be connected to the branch line connection portion is connected thereto, communication cannot be performed with a target object connected to the branch line, and thus it is possible to prevent ill effects from being exerted on a function of a control box or each accessory connected to the branch line through illegal communication. 
     [Communication- 3 ] 
     Regarding communication on a vehicle, an interface based on a plurality of standards such as CAN, CXPI, and Ethernet (registered trademark) may be used. The connected electric components may employ different communication standards for each kind of vehicle, for each grade of a vehicle, or for each area on a vehicle body. Since a device such as a special communication cable, connector, or communication interface is separately prepared in order to connect communication apparatuses based on different standards to each other, a configuration of a wire harness may be complicated and connection work may be troublesome. 
     Therefore, the vehicular circuit body is configured as described in the following (1) and (2). 
     (1) A vehicular circuit body provided in a vehicle, includes: 
     a trunk line that extends in at least a front-and-rear direction of the vehicle; 
     a plurality of control boxes that are provided in the trunk line; and 
     a branch line that directly or indirectly connects a control box to an accessory. 
     Each of the trunk line and the branch line includes a power source line and a communication line. 
     The vehicle is divided into a plurality of regions. 
     At least two control boxes are disposed in regions which are different from each other, each of which includes a gateway conversing communication methods for the communication line of the branch line and the communication line of the trunk line. 
     A plurality of the gateways can perform communication with each other via the communication line of the trunk line. 
     With this configuration, since the gateway conversing communication methods for the communication line of the trunk line and the communication line of the branch line is provided in each region of the vehicle, an accessory provided in a region is connected to a control box provided in the region via the branch line, and thus transmission and reception of signals can be performed between the accessory and the trunk line. 
     (2) In the vehicular circuit body according to the above (1), the gateway changes a communication method to correspond to a communication method used in the accessory which is connected to the gateway via the branch line. 
     With this configuration, various kinds of accessories can be connected to control boxes provided in the same regions as regions in which the accessories are provided, regardless of a communication method. 
     [Communication- 4 ] 
     On a vehicle, for example, it is desirable to connect a plurality of apparatuses transmitting a large volume of data such as video signals captured by various cameras to each other. In such an environment, optical communication may be employed so that a large capacity of communication can be performed at a high speed. However, if the entire on-vehicle system is connected by using an optical communication network, the system is inevitably very expensive. 
     Therefore, the vehicular circuit body is configured as described in the following (1) and (2). 
     (1) A vehicular circuit body provided in a vehicle, includes: 
     a trunk line that extends in at least a front-and-rear direction of the vehicle; 
     a plurality of control boxes that are provided in the trunk line; and 
     a branch line that directly or indirectly connects a control box to an accessory. 
     The trunk line includes a power source line and a communication line. 
     The branch line includes at least one of a power source line and a communication line. 
     The communication line of the trunk line has a transmission path for an optical signal, and the communication line of the branch line has a transmission path for an electric signal. 
     With this configuration, since the trunk line connecting the control boxes to each other has the transmission path for an optical signal, it is possible to increase a transmission capacity between the control boxes. Since an optical signal is used, it is hardly influenced by electromagnetic noise generated in the power source line of the trunk line or external apparatuses, and thus it is possible to increase reliability of communication. 
     (2) In the vehicular circuit body according to the above (1), at least one communication line of the trunk line directly connects two of the plurality of control boxes to each other. 
     With this configuration, two control boxes are directly connected to each other via a transmission path for an optical signal, and thus transmission and reception of signals can be performed at a high speed. 
     DESCRIPTION OF EMBODIMENTS 
     Specific embodiments related to the vehicular circuit body according to the present invention will be described with reference to drawings. 
     &lt;Configuration Example of Principal Portions&gt; 
       FIG. 1  illustrates a configuration example of principal portions of an on-vehicle device including a vehicular circuit body in an embodiment of the present invention. 
     A vehicular circuit body illustrated in  FIG. 1  is used as a transmission line required to supply power from a main power source such as an on-vehicle battery to accessories at respective vehicle body locations, that is, various electric components or to exchange signals between the electric components. In other words, a function of the vehicular circuit body of the third embodiment is the same as a general wire harness, but a structure thereof is greatly different from that of the general wire harness. 
     The on-vehicle device shown in  FIG. 1  illustrates a configuration of a vehicle interior side in the vicinity of a dash panel  16  which partitions a vehicle body into an engine room  11  and a vehicle interior (occupant compartment)  13 . As illustrated in  FIG. 1 , a reinforcement (not shown) which is a reinforcement member is provided on an instrument panel portion slightly located on a rear side of the dash panel  16  so as to extend in the leftward-and-rightward direction of the vehicle body. Principal constituent elements of the vehicular circuit body are disposed in the vicinity of the reinforcement. The vehicular circuit body at a location extending in the leftward-and-rightward direction of the vehicle body may be fixed to the reinforcement, may be fixed to the dash panel  16 , or may be fixed to a dedicated fixing tool. 
     The vehicular circuit body illustrated in  FIG. 1  includes a plurality of backbone trunk line portions  21 ,  22  and  23 , and a plurality of backbone control boxes  31 ,  32  and  33 . Each of the backbone trunk line portions  21 ,  22  and  23  includes lines such as a power source line, an earth line, and a communication line. The power source line and the earth line of each backbone trunk line portion have a configuration in which a strip-shaped metal material (for example, copper or aluminum) having a flat sectional shape is employed, and such metal materials are stacked in a thickness direction in a state of being electrically insulated from each other. Consequently, a large current is allowed to pass therethrough, and bending processing in the thickness direction is relatively facilitated. 
     The backbone trunk line portions  21  and  22  are linearly disposed in the leftward-and-rightward direction so as to be substantially parallel to the reinforcement over the reinforcement at a location along a surface of the dash panel  16 . The backbone trunk line portion  23  is disposed substantially at the center of the vehicle body in the leftward-and-rightward direction, and linearly extends in the upward-and-downward direction at the location along the surface of the dash panel  16 . The backbone trunk line portion  23  is bent in the thickness direction by about 90 degrees in the vicinity of a boundary between the dash panel  16  and a vehicle interior floor, and is disposed to extend in the front-and-rear direction of the vehicle body along the vehicle interior floor. 
     The backbone control box  32  is disposed substantially at the center of the vehicle body in the leftward-and-rightward direction, the backbone control box  31  is disposed in the vicinity of a left end in the leftward-and-rightward direction, and the backbone control box  33  is disposed in the vicinity of a right end in the leftward-and-rightward direction. 
     A left end of the backbone trunk line portion  21  is connected to a right end of the backbone control box  31 , and a right end of the backbone trunk line portion  21  is connected to a left end of the backbone control box  32 . A left end of the backbone trunk line portion  22  is connected to a right end of the backbone control box  32 , and a right end of the backbone trunk line portion  22  is connected to a left end of the backbone control box  33 . A tip end of the backbone trunk line portion  23  is connected to a lower end of the backbone control box  32 . 
     In other words, the backbone trunk line portions  21  to  23  and the backbone control boxes  31  to  33  are formed in a shape similar to a T shape as illustrated in  FIG. 1 . Internal circuits of the backbone trunk line portions  21  to  23  are in a state of being capable of being electrically connected to each other via the backbone control box  32 . 
     &lt;Details of Backbone Control Boxes&gt; 
     The backbone control box  31  disposed on the left of the vehicle body is provided with a main power source connection portion  31   a , a trunk line connection portion  31   b , and a branch line connection portion  31   c . As illustrated in  FIG. 1 , the main power source connection portion  31   a  of the backbone control box  31  is connected to a main power source cable  41 , the trunk line connection portion  31   b  is connected to the left end of the backbone trunk line portion  21 , and the branch line connection portion  31   c  is connected to a plurality of branch line sub-harnesses  42 . 
     Although not illustrated in  FIG. 1 , power source lines of two systems, an earth line, and a communication line are provided inside the backbone trunk line portion  21 . The main power source connection portion  31   a  is provided with two connection terminals which are connected to a power source line and an earth line of the main power source cable  41 . 
     For example, of the power source lines of two systems included in the backbone trunk line portion  21 , one power source line is used as a path for supplying power from the main power source. The other power source line is used as a path for supplying source power for backup, for example, when abnormality occurs. 
     A circuit board for connecting power source systems, earth systems, and communication systems of respective circuits to each other among the main power source cable  41 , the backbone trunk line portion  21 , and the branch line sub-harnesses  42  is provided inside the backbone control box  31 . 
     Regarding the main power source cable  41 , terminals connected to tip ends of the power source line and the earth line are connected to the terminals of the main power source connection portion  31   a , and are fixed by using bolts and nuts, and thus the circuits can be connected to each other. 
     Regarding the branch line sub-harnesses  42 , connectors provided at respective tip ends thereof are attachable to and detachable from the branch line connection portion  31   c , and thus the circuits can be connected to each other as necessary. Each of the branch line sub-harnesses  42  is configured to include all of a power source line, an earth line, and a communication line, or a part thereof. In the backbone control box  31  illustrated in  FIG. 1 , the branch line connection portion  31   c  is provided with six connectors, and can thus connect to six branch line sub-harnesses  42  at most. 
     As illustrated in  FIG. 1 , the backbone trunk line portions  21  to  23  and the backbone control boxes  31  to  33  are combined, and various branch line sub-harnesses  42  to  44  are connected to the backbone control boxes  31  to  33 , and thus it is possible to route various transmission lines with a simple structure similar to a backbone. 
     For example, options or various electric components additionally mounted on a vehicle can be handled just by adding or changing the branch line sub-harnesses  42  to  44  connected to any one of the backbone control boxes  31  to  33 , and thus it is not necessary to change the structure of the trunk line of the vehicular circuit body. In the present embodiment, a case is assumed in which the branch line sub-harnesses  42  to  44  are connected to the backbone control boxes  31  to  33 , but other branch line sub-harnesses (not illustrated) may be connected to locations of proper relay points on the backbone trunk line portions  21  to  23 , for example. 
     In an actual on-vehicle device, for example, as illustrated in  FIG. 1 , an electronic control unit (ECU)  51  provided in a vehicle may be connected to the backbone control box  31  or other electric components via the branch line sub-harnesses  42 . The backbone control box  32  may be connected to electronic control units  51 ,  52  and  53  or other electric components via the branch line sub-harnesses  43 . The backbone control box  33  may be connected to various electric components via the branch line sub-harnesses  44 . The respective electronic control units  51 ,  52  and  53  can control various electric components on the vehicle via communication lines of the branch line sub-harnesses  42 ,  43  and  44 , the backbone control boxes  31  to  33 , and the like. 
     On the other hand, the vehicular circuit body illustrated in  FIG. 1  is required to perform electrical connection not only between electric components in the vehicle interior  13  but also between the main power source and electric components in the engine room  11 . The dash panel  16  is disposed at a boundary between the engine room  11  and a vehicle interior  13 , and a location where an electrical connection member penetrates through the dash panel  16  is required to be perfectly sealed. In other words, the dash panel is required to have functions of insulating vibration from the engine room, reducing vibration or noise from a suspension, and blocking heat, noise, and smell in order to maintain the vehicle interior to be comfortable. Sufficient consideration is also required for the penetration location of the electrical connection member in order to prevent the functions from being impaired. 
     However, for example, if a component which has a large sectional area and is hardly bent in directions other than a specific direction, such as the backbone trunk line portions  21  to  23 , is configured to penetrate through the dash panel  16 , it is considerably hard to seal the penetration location, and thus it is also difficult to perform routing work of a vehicular circuit body. 
     In the vehicular circuit body illustrated in  FIG. 1 , the backbone trunk line portions  21  to  23  and the backbone control boxes  31  to  33  which are principal constituent elements are all disposed in a space on the vehicle interior  13  side, and thus the problem of the penetration location in the dash panel  16  can be easily solved. 
     Actually, as illustrated in  FIG. 1 , the main power source cable  41  connected to the left end of the backbone control box  31  is routed to pass through a penetration hole  16   a  of the dash panel  16 , and a circuit of the main power source in the engine room  11  is connected to a power source circuit of the backbone control box  31  via the main power source cable  41 . Consequently, power from the main power source can be supplied to the backbone control box  31 . Since an easily bendable material can be used for the main power source cable  41 , a sectional shape thereof can be made a circular shape, and a sectional area thereof can be made small, sealing of the penetration hole  16   a  can be facilitated, and thus it is also possible to prevent workability from degrading when routing work is performed. 
     In a case where various electric components in the engine room  11  are connected to the vehicular circuit body of the vehicle interior  13 , for example, a part of the branch line sub-harnesses  42  connected to the backbone control box  31  is provided to pass through the dash panel  16 , or a part of the branch line sub-harnesses  44  connected to the backbone control box  33  is provided to pass through the dash panel  16 , and thus a desired electrical connection path can be realized. In this case, since the branch line sub-harnesses  42  and  44  have small sectional areas and are easily bent, a location where the branch line sub-harnesses pass through the dash panel  16  can be easily sealed. 
     Since the main power source is located in the engine room  11  side, a power source line or an earth line may be omitted in a branch line sub-harness provided at a penetration location of the dash panel  16 , and only a communication line may be provided therein. Such a special branch line sub-harness may be configured as a communication trunk line separately from the branch line sub-harnesses  42  to  44  branched from the backbone trunk line. 
     The on-vehicle device of the present embodiment has the above-described fundamental configuration as illustrated in  FIG. 1 , but various changes or additions can be made in a configuration or an operation as will be described below for further improvement. 
     &lt;Characteristic Technique Regarding Supply of Power&gt; 
     &lt;Configuration Example of System&gt; 
     A system illustrated in  FIG. 2  includes a backbone trunk line BB_LM in order to secure principal paths for the supply of power and communication. A plurality of control boxes CB( 1 ) and CB( 2 ) are connected in the middle of the backbone trunk line BB_LM. A main battery MB and an alternator ALT which are main power sources of a vehicle side are connected to an upstream side of the backbone trunk line BB_LM. 
     Each of the control boxes CB( 1 ) and CB( 2 ) is provided with connection portions Cnx for connection to various accessories AE. The respective accessories AE correspond to electric components such as various loads or an electronic control unit (ECU) mounted on the vehicle. 
     In the configuration illustrated in  FIG. 2 , the accessory AE( 1 ) is connected to a single connector in the connection portions Cnx of the control box CB( 1 ) via a branch line sub-harness LS( 1 ). The accessory AE( 2 ) is connected to a single connector in the connection portions Cnx of the control box CB( 1 ) via a branch line sub-harness LS( 2 ). Similarly, each of the accessories AE( 3 ) and AE( 4 ) is connected to a single connector in the connection portions Cnx of the control box CB( 2 ) via corresponding branch line sub-harnesses LS( 3 ) and LS( 4 ). 
     The connection portions Cnx of each control box CB is provided with a plurality of connectors (not illustrated in  FIG. 2 ), and the plurality of connectors have the same shape, size and configuration. Therefore, in a case where each branch line sub-harness LS is connected to the connector of the connection portion Cnx, any one of the plurality of connectors may be selected. 
     Therefore, source power supplied to the backbone trunk line BB_LM from the main power source or the like branches at the location of the control box CB( 1 ) or CB( 2 ), and is supplied to each accessory AE via the branch line sub-harness LS connected to the branching location. 
     &lt;Configuration Examples of Trunk Line&gt; 
       FIGS. 3A and 3B  illustrate configuration examples of the backbone trunk line BB_LM. In the example illustrated in  FIG. 3A , the backbone trunk line BB_LM includes power source lines L 1  and L 2  of independent two systems, an earth line L 3 , and communication lines L 4  and L 5  formed of two electric wires. The power source lines L 1  and L 2 , the earth line L 3 , and the communication lines L 4  and L 5  are disposed as lines which are parallel to each other so as to extend in parallel. In an environment in which each accessory AE can be connected to the ground of the power source along other paths such as the vehicle body ground, the earth line L 3  may be omitted from the constituent elements of the backbone trunk line BB_LM. 
     In the example illustrated in  FIG. 3A , both of the power source lines L 1  and L 2  of two systems are configured to handle a common DC power source voltage of 12 V. The control box CB has a function of selecting one of the power source lines L 1  and L 2  of two systems and supplying power to a downstream side. Therefore, for example, in a case where only one of the power source lines L 1  and L 2  is disconnected in the middle of the backbone trunk line BB_LM, each control box CB can continuously supply power by using the remaining normal path. 
     In the example illustrated in  FIG. 3B , the backbone trunk line BB_LM includes power source lines L 1  and L 2 B of independent two systems, an earth line L 3 , and communication lines L 4  and L 5  formed of two electric wires. Of the power source lines L 1  and L 2 B of two systems, one power source line L 1  is configured to handle a DC power source voltage of 12 V. The other power source line L 2 B is configured to handle a DC power source voltage of 48 V. 
     Therefore, in the configuration illustrated in  FIG. 3B , the control box CB may select one of the two kinds of power source voltages and supply the selected voltage to the accessory AE under control thereof. Thus, an appropriate power source voltage may be automatically selected depending on, for example, characteristics or situations of a load. For example, in a case where the load has large power consumption, a large power source current flows and a voltage drop in a supply line path increases, and thus, it is possible to prevent an increase in a power loss by selecting a higher power source voltage. As in the example illustrated in  FIG. 3B , in a case where only one of the power source lines L 1  and L 2 B is disconnected, each control box CB can continuously supply power by using the remaining normal path. 
     In a case where two kinds of power source voltages are used, a voltage may be stepped up from 12 V to 48 V on the main power source side so as to be supplied to the backbone trunk line BB_LM, and power of 12 V supplied from the backbone trunk line BB_LM may be stepped up to be generated as power of 48 V in either of the control boxes CB. 
     &lt;Circuit Configuration Example of Power Source System&gt; 
       FIG. 4  illustrates a specific configuration example regarding a power source system in the control box CB. In this configuration, a microcomputer (CPU) CBa, a switch circuit CBb, and a bridge circuit CBc are provided in the control box CB. 
     The microcomputer CBa is configured by a field-programmable gate array (FPGA), and thus a configuration and an operation thereof can be reconfigured according to an external program rewriting instruction (reprogram). A configuration of the FPGA in the present specification is only an example. 
     The microcomputer CBa is connected to a predetermined diagnosis tool DT via a communication line Lx. Actually, there is a case where the diagnosis tool DT is connected only when adjustment or maintenance is performed in a vehicle factory, and a case where the diagnosis tool DT is normally mounted on a vehicle in order to automatically solve a problem through diagnosis performed at all times. 
     As the communication line Lx, the communication lines L 4  and L 5  of the backbone trunk line BB_LM may be used without being changed, or a dedicated communication line may be separately prepared. If a predetermined manager gives an instruction by using the diagnosis tool DT, or a predetermined recovery program is executed, the diagnosis tool DT can rewrite a program regarding a configuration and an operation of the microcomputer CBa. 
     The switch circuit CBb includes a plurality of switching elements which distribute power of a DC power source voltage (+B) supplied from the power source line L 1  or L 2  of the backbone trunk line BB_LM to a plurality of output systems, and perform switching between ON and OFF of conduction for the respective output systems. In the example illustrated in  FIG. 4 , six power field effect transistors (FETs) are used as switching elements. Each of the switching elements is configured to be turned on and off according to an output from the microcomputer CBa. Regarding an operation of the switching element, in addition to simple turning-on and turning-off, for example, an output power adjustment function may be provided by performing pulse width control (PWM) using turning-on and turning-off. 
     The bridge circuit CBc includes a plurality of switching elements for connecting the plurality of output systems located on the output side of the switch circuit CBb to each other as bridges. Each of the switching elements is also configured to be turned on and off according to an output from the microcomputer CBa. 
     &lt;Configuration Example of Power Control Function&gt; 
       FIG. 5  illustrates a specific example of a power control function CBx of the control box CB. In the example, the control box CB has six kinds of functions CBx 0 , CBx 1 , CBx 2 , CBx 3 , CBx 4  and CBx 5  illustrated in  FIG. 5  as representative power control functions. These functions are realized through processes performed by the microcomputer CBa. 
     Function CBx 0 : The microcomputer CBa detects various situations, and supplies power of all of the plurality of systems supplied from the backbone trunk line BB_LM or selectively supplies power of only one thereof to a downstream side, that is, the accessories AE sides, depending on a detected situation. For example, in a case where the backbone trunk line BB_LM has the configuration illustrated in  FIG. 3A , if disconnection of one of the power source lines L 1  and L 2  is detected, only power supplied from a normal path of the power source lines L 1  and L 2  is supplied to an output path. For example, in a case where the backbone trunk line BB_LM has the configuration illustrated in  FIG. 3B , power of higher voltage (48 V) supplied from the power source line L 2 B is preferentially selected and is output based on a specification, or preferentially selected and is output to an output system connected to the accessory AE having an actually large load current. 
     Function CBx 1 : The microcomputer CBa identifies the type of power to be supplied to each branch line. Regarding the type of power, specifically, there are “+B” power which is supplied at all times, “ACC” power whose supply is in conjunction with turning-on and turning-off of an accessory switch, and “IG” power whose supply is in conjunction with turning-on and turning-off of an ignition switch. The microcomputer CBa identifies the kind of the accessory AE connected thereto and under the control thereof, and selectively supplies power of a more appropriate type among “+B, ACC, and IG” to a corresponding branch line. Power of a type determined in advance on the basis of constant data of a program may be supplied to each branch line, and information such as an ID may be acquired from the actually connected accessory AE so that the type of power may be identified. 
     Function CBx 2 : The microcomputer CBa monitors turning-on and turning-off states of an accessory switch and an ignition switch provided in a vehicle side, and controls ON and OFF of power of each output system for each type. In other words, power is supplied to a branch line of an output system to which “ACC: accessory” is allocated as the type of power by turning on the switch circuit CBb only when the accessory switch is turned on, and power is not supplied when the accessory switch is turned off. Power is supplied to a branch line of an output system to which “IG: ignition” is allocated as the type of power by turning on the switch circuit CBb only when the ignition switch is turned on, and power is not supplied when the ignition switch is turned off 
     Function CBx 3 : The microcomputer CBa changes (reprograms) the types “+B, ACC, and IG” of source power supplied to each branch line in response to an instruction from the diagnosis tool DT. For example, the type of power output from an element “FET 4 ” of the switch circuit CBb is allocated to “IG” in a normal state. When a certain necessity for change occurs, the type of power output from the element “FET 4 ” is changed to “ACC” by executing the reprogram of the microcomputer CBa. This change influences control conditions for a control signal which is given to the element “FET 4 ” by the microcomputer CBa. In other words, in a case where “IG” is allocated as the type of power, a control signal for the element “FET 4 ” is changed according to a state of the ignition switch. In a case where “ACC” is allocated as the type of power, a control signal for the element “FET 4 ” is changed according to a state of the accessory switch. 
     Function CBx 4 : The microcomputer CBa protects a corresponding electric wire for each branch line connected to an output side. Specifically, an actually conduction current in each output system is measured, an amount of heat is calculated on the basis of the conduction current, and a corresponding system of the switch circuit CBb is interrupted before a temperature increases to a predetermined level or more. 
     Function CBx 5 : The microcomputer CBa detects a failure in each switch circuit CBb, and automatically avoids the failure so as to maintain the function in a case where the failure is detected. Specifically, adjacent output systems are connected to each other by using the bridge circuit CBc, and the supply of power to an output side is continuously performed by temporarily using a path which does not pass through an element where the failure has occurred. 
     Instead of the above “+B, ACC, and IG”, “+BA”, “IGP”, and “IGR” may be employed as a new classification of the type of power. “+BA” indicates power of a system which is turned on when a user comes close to a vehicle. “IGP” indicates power of a system which is turned on when ignition is brought into an ON state, and then an engine is in a full state. “IGR” indicates power of a system which is turned on when wheels rotate. Even in a case where such newly classified type of power is employed, the respective functions CBx 1  and CBx 2  illustrated in  FIG. 5  can be realized in the same manner by acquiring information required for control. 
     &lt;Characteristic Techniques Regarding Communication&gt; 
     &lt;Technique for Uninterrupted Communication&gt; 
       FIG. 6  illustrates a configuration example of a communication system mounted on a vehicle. A configuration illustrated in  FIG. 6  employs a communication trunk line BB_LC formed in a ring form. Although not illustrated in  FIG. 6 , the communication trunk line BB_LC is integrally formed with a wire harness for power supply or a backbone trunk line including a specially provided power source line. 
     In the configuration illustrated in  FIG. 6 , a plurality of control boxes CB( 1 ) to CB( 4 ) are connected in the middle of the communication trunk line BB_LC in a distribution manner. Accessories AE( 1 ) to AE( 4 ) are respectively connected to and under the control of the control boxes CB( 1 ) to CB( 4 ) via branch line sub-harnesses LS( 1 ) to LS( 4 ). The accessories AE correspond to electric components such as various loads or an electronic control unit (ECU) disposed on a vehicle. 
     Each of the plurality of control boxes CB( 1 ) to CB( 4 ) has a function of supplying power diverging from a trunk line to the accessory AE via the branch line sub-harness LS, or branching a communication path passing through the communication trunk line BB_LC. Each branch line sub-harness LS includes a power source line and a communication line. The branch line sub-harness LS may include an earth line. 
     In a system having the configuration illustrated in  FIG. 6 , a case is assumed in which communication is performed between the accessory AE( 1 ) and the accessory AE( 2 ). In this case, in the communication trunk line BB_LC in a ring form, a path between the control box CB( 1 ) and the control box CB( 2 ) is used, and thus communication can be performed along the shortest path. 
     Further, a part of the communication trunk line BB_LC may be disconnected. However, even if the communication trunk line BB_LC is disconnected on the path between the control box CB( 1 ) and the control box CB( 2 ), the entire path has a ring form, and thus another path may be used. In other words, a communication path reaching the control box CB( 2 ) from the control box CB( 1 ) via the control box CB( 4 ) and the control box CB( 3 ) can be used, and thus a communication path between the accessory AE( 1 ) and the accessory AE( 2 ) is not interrupted. 
     The communication trunk line BB_LC in a ring form as illustrated in  FIG. 6  may also be applied to a communication system having a linear path, such as the backbone trunk line BB_LM illustrated in  FIG. 2 , without being changed. For example, two trunk lines such as a communication trunk line BB_LC for a forward route and a communication trunk line BB_LC for a backward route are disposed on the linear backbone trunk line BB_LM in parallel to each other as a set, and ends of the communication trunk lines BB_LC for a forward route and a backward route are connected to each other, and thus a communication path in a ring form, that is, in a closed loop can be configured. 
     &lt;Security Technique for Connection Portion&gt; 
     &lt;Protection Using Physical Means&gt; 
       FIGS. 8A, 8B and 8C  illustrate specific examples of techniques for physically protecting the connection portion Cnx of each control box CB. A circuit board CBd illustrated in  FIGS. 8A, 8B and 8C  is provided in each control box CB. 
     Each of the control boxes CB( 1 ) to CB( 4 ) has the connection portions Cnx including a plurality of connectors so as to be connected to various accessories AE via the branch line sub-harnesses LS or the like. The connectors are configured to be suitable for a predetermined standard such as the universal serial bus (USB), and the plurality of connectors are disposed to be arranged side by side for connection to a plurality of apparatuses. 
     However, in a specific control box CB, none of the connectors of the connection portion Cnx may be used, or some of the connectors of the connection portion Cnx may not be used, due to a difference in a vehicle model, a difference in a grade, a difference in a destination, and a difference in an option selected by a user purchasing a vehicle. If a configuration of each control box CB is changed so as to reflect the difference in the vehicle model, the difference in the grade, the difference in the destination, or the like, such a configuration cannot be used in common, and thus the number of control boxes CB is increased, thereby also increasing manufacturing cost. 
     On the other hand, in a case where a connector in an unoccupied state in which no branch line sub-harness LS is connected thereto in a defined vehicular default state is present in the connection portion Cnx, a user or a third party may freely and illegally connect a certain apparatus to the connector in an unoccupied state. Physical configurations illustrated in  FIGS. 8A, 8B and 8C  are used to prevent such illegality. 
     In the configuration illustrated in  FIG. 8A , a case is assumed in which none of six connectors of the connection portion Cnx are used. Therefore, openings of all of the connectors are closed by using a physical cover Kc 1  with a key so that none of the connectors of the connection portion Cnx are freely used. 
     The cover Kc 1  with a key is a cover covering an outside of the connection portion Cnx, and can be fixed to the connection portion Cnx correctly. The cover Kc 1  with a key has a key mechanism built therein, and has a structure in which fixation of the cover Kc 1  with a key cannot be unlocked unless an operation is performed by using a physical unlock key Kk prepared in advance. Therefore, a person without the unlock key Kk cannot illegally connect any apparatus to the connectors of the connection portion Cnx. 
     In the configuration illustrated in  FIG. 8B , a case is assumed in which the predetermined branch line sub-harnesses LS or the like are connected to some connectors of the connection portion Cnx, and remaining connectors are in an unoccupied state. Therefore, in the connection portion Cnx, openings or the like of the connectors in an unoccupied state are individually closed by using a physical cover Kc 2  with a key so that the connectors are not freely used. 
     The cover Kc 2  with a key is structurally fixed to a connector in a state of closing a corresponding single opening as a result of being attached to one of the six connectors having the same shape and size in the connection portion Cnx. In the same manner as the cover Kc 1  with a key, the cover Kc 2  with a key has a key mechanism built therein, and has a structure in which fixation of the cover Kc 2  with a key cannot be unlocked unless an operation is performed by using a physical unlock key Kk prepared in advance. 
     In the configuration illustrated in  FIG. 8C , a case is assumed in which the predetermined branch line sub-harnesses LS or the like are connected to some connectors of the connection portion Cnx, and remaining connectors are in an unoccupied state. Therefore, in the connection portion Cnx, openings or the like of the connectors in an unoccupied state are individually closed by using a physical seal Ks for sealing so that the connectors are not freely used. There may be a configuration in which openings of a plurality of connectors are collectively covered with a single seal Ks for sealing. 
     For example, the seal Ks for sealing is formed in an elongated and thin tape form, and is made of a resin. For example, a special pattern is formed on a surface of the seal Ks for sealing through printing so as to be clearly differentiated from other seals generally available in the market. Both ends of the seal Ks for sealing in a longitudinal direction are fixed to the connection portion Cnx via an adhesive or the like. 
     In a case where a user or the like illegally uses a specific connector whose opening is covered with the seal Ks for sealing so as not to be used, the seal Ks for sealing is broken or the adhesive location is torn off, and thus signs of removing the seal can be physically left. In other words, illegal use of a connector can be easily confirmed by a predetermined manager or the like after the illegal use is performed. 
     &lt;Protection Based on Control&gt; 
       FIG. 9  illustrates a specific example of a technique for protecting the connection portion Cnx of each control box CB on the basis of electrical control. In other words, a microcomputer (not illustrated) provided on the circuit board CBd performs control illustrated in  FIG. 9 , and thus protects an unused connector of the connection portion Cnx from illegal use. 
     The microcomputer on the circuit board CBd recognizes whether or not each connector of the connection portion Cnx managed by the microcomputer is used on the basis of a program and constant data written in advance by using a diagnosis tool. The microcomputer monitors voltages at a plurality of terminals provided in the respective connectors, and can thus actually detect whether or not a certain apparatus is connected to a connector. 
     In step S 11 , the microcomputer monitors whether or not each communication port connector is connected for each connector. If new connection to each connector is detected in step S 12 , the flow proceeds to step S 13 . In a case where the connector to which a new connection is detected is registered as an unused connector, the flow proceeds to the next step S 14 , and a process of detecting illegal connection is performed. 
     Through the process in step S 14 , for example, data indicating the illegal use is preserved in a nonvolatile memory, or abnormality display regarding the illegal use is performed on a display such as a meter unit. Communication using a corresponding connector may be automatically interrupted so that illegal use of an apparatus is prevented. 
     &lt;Technique for Mutually Connecting Communication Networks and Communication Apparatuses Based on Various Specifications&gt; 
       FIG. 7  illustrates a configuration example of a communication system mounted on a vehicle. The communication system illustrated in  FIG. 7  includes a communication trunk line BB_LC. Although not illustrated in  FIG. 7 , the communication trunk line BB_LC is integrally formed with a wire harness for power supply or a backbone trunk line including a specially provided power source line. The backbone trunk line is provided with an earth line as necessary. 
     In the configuration illustrated in  FIG. 7 , a plurality of control boxes CB( 1 ), CB( 2 ) and CB( 3 ) are connected to the communication trunk line BB_LC used in common in a state of being distributed to a plurality of areas AR 1 , AR 2  and AR 3 . Specific examples of the areas AR 1 , AR 2  and AR 3  may include an engine room, an instrument panel region, a floor region, and a luggage room. 
     Each of the control boxes CB( 1 ) to CB( 3 ) has a function of dividing power supplied to a trunk line so as to supply the power to the accessory AE, or a function of branching a path of a communication line so as to secure a connection path. In the configuration illustrated in  FIG. 7 , each of the plurality of control boxes CB( 1 ), CB( 2 ) and CB( 3 ) includes a gateway GW. 
     Each of the plurality of gateways GW( 1 ) to GW( 3 ) illustrated in  FIG. 7  fundamentally has a function of connecting networks or apparatuses based on different specifications such as communication protocols to each other. 
     For example, in a system on a vehicle, communication apparatuses or networks based on various standards using different specifications, such as Controller Area Network (CAN), CAN with Flexible Data Rate (CAN_FD), Clock Extensible Peripheral Interface (CXPI), Ethernet (registered trademark), and an optical communication network, may be employed for each area, each vehicle model, and the like. The gateway GW absorbs such a difference between the specifications, and thus apparatuses having different specifications can be communicably connected to each other. 
     In the configuration illustrated in  FIG. 7 , a gateway GW is respectively provided in the control box CB for each area, and thus communication lines can be connected to each other by using the gateway GW even if a communication specification differs for each area. 
     &lt;Technique for Enabling High-Speed Communication and Technique for Gateway&gt; 
       FIG. 10  illustrates configuration examples of the control box CB having an optical communication function and a gateway function and a communication system of the backbone trunk line BB_LM.  FIG. 11  illustrates a configuration example for supplying source power to a communication system. 
     Also in the system illustrated in  FIG. 10 , the control box CB is connected to the backbone trunk line BB_LM. The backbone trunk line BB_LM illustrated in  FIG. 10  includes power source lines L 1  and L 2 , an earth line L 3 , and communication lines L 4 B and L 5 B. In  FIG. 10 , GND indicates the ground, that is, the earth. 
     In the example illustrated in  FIG. 10 , the power source line L 1  is connected to a main battery (BATT) of the vehicle, and the power source line L 2  is connected to a sub-battery. The communication lines L 4 B and L 5 B are formed of optical fibers so as to cope with optical communication. The optical communication is employed in the trunk line, and thus high-speed communication can be performed at various locations on the vehicle. Also, it is hard to be influenced by noise. 
     The control box CB illustrated in  FIG. 10  copes with each communication function in Ethernet (Trademark), CAN_FD, and CXPI in addition to the optical communication. Specifically, eight sets of communication port connectors CP 1  to CP 8  are provided in the control box CB. The communication port connectors CP 1  and CP 2  are communication ports for use only in Ethernet (Trademark), and each of the communication port connectors CP 3  to CP 8  is a communication port for which one of specifications such as CAN_FD and CXPI is selectable. Each of the eight sets of communication port connectors CP 1  to CP 8  has a specification corresponding to a metal communication line. A branch line has a metal specification, and thus component cost of the branch line can be reduced. 
     As illustrated in  FIG. 10 , the control box CB includes a power source circuit CB 01 , a gateway control circuit CB 02 , PHY circuits CB 03 , CB 04 , CB 05  and CB 06 , network switches CB 07  and CB 08 , transceivers CB 09  and CB 10 , and a switching circuit CB 11 . 
     The power source circuit CB 01  is connected to the power source lines L 1  and L 2  and the earth line L 3 , and a power source voltage, for example, “+5 V” required in each circuit such as the gateway control circuit CB 02  is generated on the basis of source power supplied from the backbone trunk line BB_LM. 
     The gateway control circuit CB 02  is formed of a microcomputer, and realizes a function of a gateway (GW). In other words, protocol conversion between communications based on different standards or signal switching control is performed. A control signal for switching in the switching circuit CB 11  is also generated. 
     The PHY circuits CB 03 , CB 04 , CB 05  and CB 06  provide an interface function of a physical layer in Ethernet (Trademark). Each of the PHY circuits CB 03  and CB 04  has a function of performing mutual conversion between an optical signal and an electric signal or mutual conversion between a digital signal and an analog signal so as to correspond to two wavelengths of the optical signal. Each of the PHY circuits CB 05  and CB 06  has a function of performing mutual conversion between a digital signal and an analog signal so as to correspond to a signal based on the metal standard of Ethernet (Trademark). 
     The network switches CB 07  and CB 08  are switch circuits corresponding to the standards of Ethernet (Trademark), and have a function of determining whether or not transmission to each connected apparatus is to be performed by taking into consideration a destination of received data. 
     In the configuration illustrated in  FIG. 10 , the network switch CB 07  has a function of controlling a chassis system and a power train system on the vehicle system. The network switch CB 08  has a function of controlling a body system, an entertainment system, a driving assistance system, and a high-grade driving assistance system on the vehicle system. The network switch CB 07  is connected between the PHY circuits CB 03  and CB 04 , and the gateway control circuit CB 02 . The network switch CB 08  is connected between the PHY circuits CB 03  to CB 06 , and the gateway control circuit CB 02 . 
     The transceivers CB 09  and CB 10  are connected between the gateway control circuit CB 02  and the switching circuit CB 11 . The transceiver CB 09  has a function of transmitting and receiving signals corresponding to the standard of CAN_FD. The transceiver CB 10  has a function of transmitting and receiving signals corresponding to the standard of CXPI. 
     The switching circuit CB 11  has a switching function of enabling CAN_FD using two communication lines and CXPI using a single communication line to be used by the common communication port connectors CP 3  to CP 8 . Specifically, the switching circuit CB 11  has twelve switching elements for switching between signals which are input to the respective communication port connectors CP 3  to CP 8 . Turning-on and turning-off of the switching elements are controlled on the basis of control signals output from the gateway control circuit CB 02 , and thus signals suitable for any one of CAN_FD and CXPI can be used by the communication port connectors CP 3  to CP 8 . 
     For example, in a case where an accessory AE such as cameras or various sensors requiring a relatively high communication speed is connected to and under the control of the control box CB, it is possible to satisfy a specification required for high-speed communication by using, for example, the communication port connector CP 1  or CP 2 . In a case where an accessory AE performing relatively low-speed communication is connected, it is possible to ensure a necessary minimum communication function by using the communication port connectors CP 3  to CP 8 . 
       FIG. 11  illustrates a circuit configuration example for supplying source power to each of the communication port connectors CP 1  to CP 8 . In the configuration illustrated in  FIG. 11 , terminals CBz 1  and CBz 2  provided in the control box CB are connected to a main power source. Specifically, the terminal CBz 1  is connected to a positive electrode of the main battery MB via a fusible link FL built in the main battery MB. The terminal CBz 2  of the control box CB is connected to a negative electrode of the main battery MB. The terminals CBz 1  and CBz 2  are respectively connected to the power source line L 1  and the earth line L 3  of the backbone trunk line BB_LM. The power source line L 2  of the backbone trunk line BB_LM is connected to a positive electrode of a sub-battery (not illustrated). 
     A power source circuit CB 01   a  for supplying source power to each of the communication port connectors CP 1  to CP 8  of eight systems is built in the control box CB. The power source circuit CB 01   a  includes switch circuits SW 01  and SW 02 , and diodes D 1  and D 2  for each system regarding the communication port connector. 
     Each of the switch circuits SW 01  and SW 02  is formed as a circuit in which a switching element whose turning-on and turning-off can be controlled by a control circuit of the control box CB is connected in series to a fuse. The diodes D 1  and D 2  have a function of preventing a reverse current. 
     Therefore, if, of the switch circuits SW 01  and SW 02 , only the switch circuit SW 01  is turned on, power from the main power source can be supplied to each of the communication port connectors CP 1  to CP 8 . If, of the switch circuits SW 01  and SW 02 , only the switch circuit SW 02  is turned on, power from the sub-power source can be supplied to each of the communication port connectors CP 1  to CP 8 . 
     &lt;Special Optical Communication Technique&gt; 
     &lt;Combination of a Plurality of Communication Paths&gt; 
       FIG. 54  illustrates a configuration example of a communication system of an on-vehicle system. The on-vehicle system illustrated in  FIG. 54  includes five control boxes CB( 1 ) to CB( 5 ). Three control boxes CB( 1 ), CB( 2 ) and CB( 3 ) are connected to each other via a communication trunk line BB_LC configured in a ring form. A peer-to-peer (P2P) communication line LPP 1  is connected between the control box CB( 1 ) and the control box CB( 4 ), and a P2P communication line LPP 2  is connected between the control box CB( 1 ) and the control box CB( 5 ). Optical communication is used for all of the communication trunk line BB_LC, and the communication lines LPP 1  and LPP 2 . 
     In a case where the optical communication is used, each relay node on a communication path corresponding to the control box CB performs a process of converting a received optical signal into an electrical signal, converting the electrical signal to an optical signal again, and sending the optical signal to a transmission path. Therefore, a delay of an optical signal occurs for each relay node. In a case where a communication path of the entire system is configured in a ring form, a delay of an optical signal increases due to an increase in the number of connected relay nodes. 
     On the other hand, since, in the on-vehicle system illustrated in  FIG. 54 , the communication trunk line BB_LC having a ring form and the P2P communication lines LPP 1  and LPP 2  are combined with each other, a signal delay can be reduced, and high-speed communication can be performed. In other words, since the number of nodes on the communication trunk line BB_LC having a ring form is three, a delay occurring on the ring can be minimized 
     Therefore, for example, in a case where optical communication is performed between the control box CB( 3 ) and the control box CB( 4 ), a signal delay is reduced, and thus high-speed communication can be performed, compared with a case where the entire communication path is configured in a ring form. 
     Since the communication trunk line BB_LC having a ring form is provided, there is redundancy in the communication path, and thus reliability of communication is improved. In other words, in a case where disconnection occurs at a single location on the communication trunk line BB_LC, communication can be performed by using other paths which are not disconnected. A trunk line may be formed of a transmission path for optical communication, a branch line may be formed of a transmission path for an electrical signal, and these may be combined with each other. 
     &lt;Simultaneous Use of Optical Signals with a Plurality of Wavelengths&gt; 
       FIG. 55  illustrates a configuration example of a section of the communication trunk line BB_LC in the on-vehicle system illustrated in  FIG. 54 . In other words, as illustrated in  FIG. 55 , the communication trunk line BB_LC illustrated in  FIG. 54  includes an optical fiber cable FBC 1  forming a forward route and an optical fiber cable FBC 2  forming a backward route. Each of the optical fiber cables FBC 1  and FBC 2  has two optical fibers FB 11  and FB 12  built therein. 
     In the present embodiment, both of a specific wavelength λ 1  and a wavelength λ 2  which is different from the wavelength λ 1  are respectively used for handled optical signals. As illustrated in  FIG. 55 , one optical fiber cable FBC 1  transmits an optical signal having the wavelength λ 1 , and the other optical fiber cable FBC 2  transmits an optical signal having the wavelength λ 2 . 
     Therefore, two communication paths can be secured together by using optical signals corresponding to two wavelengths on the communication trunk line BB_LC, and thus redundancy can be provided. Consequently, it is possible to improve reliability of communication. 
     As a specific example, optical signals corresponding to two kinds of wavelengths are used depending on importance or priority. For example, a signal used to control an important load on a vehicle is allocated to an optical signal having the wavelength λ 1 , and a signal used to control a load having low importance is allocated to an optical signal corresponding to the wavelength λ 2 . In a case where communication using an optical signal having the wavelength λ 1  on which an important load is put is interrupted, information to be transmitted is automatically transmitted by using an optical signal having the wavelength λ 2 . Consequently, it is possible to secure a path for continuously performing communication. This control may be performed by using a microcomputer on each control box CB. 
     &lt;Use of Wavelength Multiplexing/Time Division Multiplexing (TDM)&gt; 
       FIG. 56  illustrates a configuration example of an optical signal on which wavelength multiplexing and time division multiplexing are performed.  FIG. 57  illustrates a configuration example of a communication system of an on-vehicle system performing optical wavelength multiplex communication. 
     For example, in a case where an optical signal having the wavelength λ 1  and an optical signal having the wavelength λ 2  are used together, the wavelengths of the two optical signals are different from each other, and thus the signals may be transmitted with a single optical fiber through wavelength multiplexing as in  FIG. 56 . 
     Therefore, either one of the two optical fibers FB 11  and FB 12  illustrated in  FIG. 55  can be omitted. High priority may be allocated to the optical signal having the wavelength λ 1 , and low priority may be allocated to the optical signal having the wavelength λ 2 . The optical signals are subjected to time division multiplexing, and thus optical signals ch 1 , ch 2  and ch 3  of a plurality of channels can be sequentially transmitted as illustrated in  FIG. 56  by a single communication line. 
     In the on-vehicle system illustrated in  FIG. 57 , three control boxes CB( 1 ), CB( 2 ) and CB( 3 ) are connected to each other via the communication trunk line BB_LC. The communication trunk line BB_LC illustrated in  FIG. 57  is formed of an optical fiber for a forward route and an optical fiber a backward route, and is configured in a ring form as a whole. 
     An optical signal subjected to wavelength multiplexing and time division multiplexing is sent onto a single optical fiber of the communication trunk line BB_LC as illustrated in  FIG. 56 , and thus optical communication can be performed between the control box CB( 1 ) to the control box CB( 3 ). 
     Each of the control boxes CB( 1 ) to CB( 3 ) illustrated in  FIG. 57  includes a reception side circuit and a transmission side circuit. The reception side circuit includes a splitter  57 - 1 , optical/electrical conversion units (O/E)  57 - 2  and  57 - 3 , branching units (DROP)  57 - 4  and  57 - 5 , and a time division demultiplexer  57 - 6 . The transmission side circuit includes a time division multiplexer  57 - 7 , inserting units (ADD)  57 - 8  and  57 - 9 , and electrical/optical conversion units (E/O)  57 - 10  and  57 - 11 . 
     In other words, in the control boxes CB( 1 ) to CB( 3 ), an optical signal is incident to the reception side circuit from the single optical fiber of the communication trunk line BB_LC. The optical signal is divided into two optical signals respectively having the wavelengths λ 1  and λ 2  in the splitter  57 - 1 . The divided optical signal having the wavelength λ 1  is converted into an electrical signal by the /optical/electrical conversion unit  57 - 2 , and branches into two systems in the branching unit  57 - 4 . One branched electrical signal is input to the time division demultiplexer  57 - 6 , and the other electrical signal is input to the transmission side circuit. 
     Similarly, the divided optical signal having the wavelength λ 2  is converted into an electrical signal by the optical/electrical conversion unit  57 - 3 , and branches into two systems in the branching unit  57 - 5 . One branched electrical signal is input to the time division demultiplexer  57 - 6 , and the other electrical signal is input to the transmission side circuit. The time division demultiplexer  57 - 6  divides the input electrical signals which are output from the branching units  57 - 4  and  57 - 5  for each time, so as to generate signals of a plurality of channels (ch 1 , ch 2 , and ch 3 ). 
     For example, the control box CB( 1 ) sends a received signal of a first channel output from the time division demultiplexer  57 - 6  to accessory AE 11  (ADAS ECU). The control box CB( 2 ) may use a received signal of a second channel output from the time division demultiplexer  57 - 6 . The control box CB( 3 ) sends a received signal of a third channel output from the time division demultiplexer  57 - 6  to accessory AE 31  (rear monitor). 
     In the transmission side circuit of the control box CB( 1 ), a signal for an accessory AE 12  (ridar) is input to the time division multiplexer  57 - 7  as a signal having high priority, and a signal for an accessory AE 13  (DVD player) is input to the time division multiplexer  57 - 7  as a signal having low priority, by using the channel (ch 1 ) allocated to this control box CB. The time division multiplexer  57 - 7  allocates the input signals of two systems respectively to corresponding timings of the channel, so as to generate electrical signals subjected to time division multiplexing. The signal having high priority and the signal having low priority are respectively input to the inserting units  57 - 8  and  57 - 9  from the time division multiplexer  57 - 7 . 
     The inserting unit  57 - 8  generates a signal obtained by combining the received signal with the output from the time division multiplexer  57 - 7  for each channel with respect to the signal having high priority. The inserting unit  57 - 9  generates a signal obtained by combining the received signal with the output from the time division multiplexer  57 - 7  for each channel with respect to the signal having low priority. 
     The output signal from the inserting unit  57 - 8  is converted into an optical signal having the wavelength λ 1  by the electrical/optical conversion unit  57 - 10 . The output signal from the inserting unit  57 - 9  is converted into an optical signal having the wavelength λ 2  by the electrical/optical conversion unit  57 - 11 . The optical signal having the wavelength λ 1  output from the electrical/optical conversion unit  57 - 10  and the optical signal having the wavelength λ 2  output from the electrical/optical conversion unit  57 - 11  are simultaneously supplied to a single common optical fiber of the communication trunk line BB_LC, and are transmitted as an optical signal subjected to wavelength multiplexing. 
     Similarly, in the transmission side circuit of the control box CB( 2 ), a signal for an accessory AE 21  (camera) is input to the time division multiplexer  57 - 7  as a signal having high priority, and a signal for an accessory AE 22  (camera) is input to the time division multiplexer  57 - 7  as a signal having low priority, by using the channel (ch 2 ) allocated to this control box CB. In the transmission side circuit of the control box CB( 3 ), a signal for an accessory AE 32  (camera) is input to the time division multiplexer  57 - 7  as a signal having high priority by using the channel (ch 3 ) allocated to this control box CB. 
     In any case, in the communication system of the on-vehicle system illustrated in  FIG. 57 , an optical signal subjected to wavelength multiplexing and time division multiplexing can be transmitted by using a single optical fiber of the communication trunk line BB_LC as illustrated in  FIG. 56 . 
     In the on-vehicle system illustrated in  FIG. 57 , both of the two kinds of wavelengths λ 1  and λ 2  are used, and signal processing is separately performed for each wavelength. A difference between the wavelengths is correlated with a difference between priorities. Therefore, in a case where a failure occurs in communication using either one of the two kinds of the wavelengths λ 1  and λ 2 , for example, switching control may be performed so that a normal communication line is used for transmitting a signal having high priority. A communication path can be secured with only a single optical fiber. 
     &lt;Other Characteristic Techniques&gt; 
     &lt;Technique of Reducing the Number of Components of Wire Harness&gt; 
       FIG. 12  is an exploded view illustrating a configuration example of a wire harness obtained by combining a printed circuit board with electric wires. 
     A configuration of a wire harness may variously change depending on a difference in a vehicle model, a difference in a grade, a difference in a destination, and a difference in an option. If the configuration changes, it is necessary to individually add a component number to each component for each configuration. If the number of kinds of configurations increases, the number of components increases and thus manufacturing also increases. 
     Therefore, a constituent element of a wire harness is divided into a base in which a configuration does not change and an addition in which a configuration changes. As in a backbone member  12 - 1  illustrated in  FIG. 12 , a circuit formed on a printed circuit board (PCB) is used as an addition element of a wire harness, a sub-harness  12 - 2  formed of electric wires is used as a base element of the wire harness, and the entire wire harness is configured by combining the addition element with the base element. 
     Here, the circuit formed on the printed circuit board is easily configured as an electronic circuit, and has, for example, a field-programmable gate array (FPGA) device built therein so as to rewrite a program, and thus a circuit configuration can be easily changed. Thus, hardware common to all elements can be employed in the backbone member  12 - 1 , and thus it is possible to prevent an increase in the number of components. 
     &lt;Technique for Coping with Connection of Post-Installation Apparatus or Carry-in Apparatus&gt; 
       FIG. 13  is a perspective view illustrating an example of an exterior of a control box having USB ports. 
     A control box  13 - 1  illustrated in  FIG. 13  is connected to a backbone trunk line  12 - 0 , and includes a plurality of standard communication ports  13 - 2  so as to be connected to predetermined branch line harnesses. Specifically, a plurality of connectors having a communication function based on a universal serial bus (USB) standard are provided in the standard communication ports  13 - 2 . Therefore, various apparatuses can be connected to the backbone trunk line  12 - 0  via the control box  13 - 1  as long as the apparatus has a standardized communication port. In other words, it is easy to post-install various apparatuses or to connect an apparatus carried in a vehicle by a user. 
     &lt;Technique for Diversifying Functions of Control Box or the Like&gt; 
       FIGS. 14A, 14B and 14C  are plan views illustrating three configuration examples of circuit boards built in a control box or the like. 
     In a wire harness or the like of a vehicle, functions to be supported greatly change depending on the kind of a vehicle model, the kind of a grade, the kind of a destination, the kind of an option, and the like. For example, the number of circuits, a current capacity, a processing speed, and the number of processes with which each control box on a backbone trunk line should cope change depending on a grade or the like of a vehicle. If functions satisfying all needs are installed in control boxes of all grades, the minimum cost increases, and thus a low cost vehicle cannot be provided. However, if a control box having a configuration optimal for each of various combinations of vehicle models, grades, destinations, options, and the like is prepared, the number of components considerably increases, and thus cost increases. 
     Therefore, as illustrated in  FIGS. 14A, 14B and 14C , an increase in the number of components is prevented by using a component in common. Specifically, a necessary circuit function is realized by combining the standardized circuit boards  14 - 1 A,  14 - 1 B and  14 - 1 C of three kinds with a microcomputer  14 - 2  formed of an FPGA. 
     The circuit board  14 - 1 A is a circuit board for a grade A which is the highest of three grades. The circuit board  14 - 1 B is a circuit board for a grade B which is the second highest of three grades. The circuit board  14 - 1 C is a circuit board for a grade C which is the lowest of three grades. The circuit boards  14 - 1 A,  14 - 1 B and  14 - 1 C of three kinds have different sizes (large, medium, and small), and can thus cope with a change in the number of circuits through selection of the boards. The number of microcomputers  14 - 2  is changed in order to cope with a change in the number of circuits. 
     In other words, since the number of circuits to cope with is small in a case of a low grade vehicle, the small-sized circuit board  14 - 1 C is combined with a single microcomputer  14 - 2  so as to realize a necessary function as illustrated in  FIG. 14C . Since the number of circuits to cope with is intermediate in a case of an intermediate grade vehicle, the medium-sized circuit board  14 - 1 B is combined with two microcomputers  14 - 2  so as to realize a necessary function as illustrated in  FIG. 14B . Since the number of circuits to cope with is large in a case of a high grade vehicle, the large-sized circuit board  14 - 1 A is combined with three microcomputers  14 - 2  so as to realize a necessary function as illustrated in  FIG. 14A . 
     Each microcomputer  14 - 2  is an FPGA, and a program thereof is easily rewritten. Therefore, the program of each microcomputer  14 - 2  is rewritten in order to cope with a difference between various specifications such as a grade of a vehicle. 
     Therefore, in a case of employing the configurations illustrated in  FIGS. 14A, 14B and 14C , any one of the three kinds of circuit boards  14 - 1 A,  14 - 1 B and  14 - 1 C and one kind of microcomputer  14 - 2  have only to be prepared, and thus it is possible to prevent increases in the number of kinds of components and the number of components. 
     &lt;Technique for Reducing the Number of Components Such as Trunk Line&gt; 
       FIG. 15  is a perspective view illustrating a configuration example of a connection location of a routing member forming a trunk line. 
     For example, in a case of forming large-sized routing members such as the backbone trunk line portions  21 ,  22  and  23  illustrated in  FIG. 1 , a single routing member may be configured by combining a plurality of components used in common with each other in order to prevent an increase in the number of kinds of components or an increase in the number of components due to a difference between specifications such as configurations or shapes. 
     In the configuration example illustrated in  FIG. 15 , two thin tabular routing members  15 - 1  and  15 - 2  are connected to each other by butting facing surfaces thereof, so as to be integrated. Specifically, as illustrated in  FIG. 15 , a protrusion  15 - 1   a  is formed on a right end surface of the routing member  15 - 1 , and a concave  15 - 2   a  having a shape complementary to that of the protrusion  15 - 1   a  is formed on a left end surface of the routing member  15 - 2 . 
     A plurality of electrodes  15 - 3  respectively connected to a power source line (+12 V), the ground (GND), and a predetermined signal line are disposed to be exposed to the right end surface of the routing member  15 - 1 . Although not illustrated, similarly, electrodes which can be respectively brought into contact with the electrodes  15 - 3  are also disposed on the left end surface of the routing member  15 - 2 . 
     As mentioned above, the types of the routing members  15 - 1  and  15 - 2  in which shapes of connection locations, electrode specifications, and the like are standardized in advance, are selected, and the selected members are combined with each other, so that the routing member corresponding to various specifications can be configured. In this case, it is possible to reduce the number of types of standardized routing members and also to reduce the number of components. 
     &lt;Technique for Coping with Change in Connection Specification&gt; 
       FIG. 16  is a plan view illustrating a connection example between a control box on the trunk line and branch line sub-harnesses. 
     A control box  16 - 1  illustrated in  FIG. 16  is connected to, for example, the backbone trunk line portions  21 ,  22  and  23  illustrated in  FIG. 1 . The whole function or specification of a wire harness is determined according to an order of a user who has ordered a vehicle, and predetermined branch line sub-harnesses  16 - 2 A,  16 - 2 B,  16 - 2 C and  16 - 2 D are connected to connection portions of the control box  16 - 1 . 
     A microcomputer whose program is easily rewritten is mounted on the control box  16 - 1 . When such a wire harness is manufactured, a conduction checker  16 - 3  is prepared to check whether or not there is the occurrence of conduction between each terminal of the branch line sub-harnesses  16 - 2 A,  16 - 2 B,  16 - 2 C and  16 - 2 D and each terminal of the control box  16 - 1  through actual connection. When the program of the microcomputer on the control box  16 - 1  is rewritten with a predetermined tool, the content of the program is rewritten so as to reflect an actual conduction state in conjunction with the conduction checker  16 - 3 . 
     Therefore, actually, a worker appropriately rewrites the program so that the kinds of branch line sub-harnesses  16 - 2 A,  16 - 2 B,  16 - 2 C and  16 - 2 D assembled to the control box  16 - 1 , or a difference between connection positions is reflected, and thus switching between circuit connection states in the actual control box  16 - 1  can occur automatically. Thus, productivity of a wire harness is improved. 
     &lt;Technique for Coping with Change in Connection Specification&gt; 
       FIG. 17  is a plan view illustrating a connection example between a control box on the trunk line and branch line sub-harnesses. 
     A control box  17 - 1  illustrated in  FIG. 17  is connected to, for example, the backbone trunk line portions  21 ,  22  and  23  illustrated in  FIG. 1 . The whole function or specification of a wire harness is determined according to an order of a user who has ordered a vehicle, and predetermined branch line sub-harnesses  17 - 2 A,  17 - 2 B,  17 - 2 C and  17 - 2 D are connected to connection portions of the control box  17 - 1 . 
     Here, each of the branch line sub-harnesses  17 - 2 A,  17 - 2 B,  17 - 2 C and  17 - 2 D has a communication function, and transmits unique identification information (ID) pre-allocated thereto to a microcomputer of the control box  17 - 1  which is a connection destination. The microcomputer identifies any one of, for example, “ABCD”, “ABDC”, and “ACDB” as combinations of IDs transmitted from the branch line sub-harnesses  17 - 2 A,  17 - 2 B,  17 - 2 C and  17 - 2 D which are actually connected thereto, and thus automatically selects a pattern of software which is to be applied to a connection destination of each branch line. 
     Therefore, a worker can freely select a connection position of each of various branch line sub-harnesses  17 - 2 A,  17 - 2 B,  17 - 2 C and  17 - 2 D, and thus productivity is improved. Even in a case where any accessory is post-installed, the microcomputer can automatically cope with the accessory if the microcomputer recognizes the accessory in advance. 
     &lt;Technique for Coping with Change in Connection Specification&gt; 
       FIGS. 18A and 18B  are plan views illustrating connection examples between a trunk line and branch line sub-harnesses. 
     As illustrated in  FIG. 18A , in a case where a backbone formed of a trunk line  18 - 1  and a plurality of control boxes  18 - 2  and  18 - 3  is connected to various accessories via various branch line sub-harnesses  18 - 4  and  18 - 5 , positions of connectors for connection of the respective branch line sub-harnesses  18 - 4  and  18 - 5  may change, or pin arrangement of the connectors may change. 
     For example, in the example illustrated in  FIG. 18B , a case is assumed in which either one of an automatic air conditioner  18 - 6 A and a manual air conditioner  18 - 6 B which are accessories is selectively connected to a connector  18 - 2   b  of the control box  18 - 2  according to a change in a specification. In this case, pin arrangement of a connector for the automatic air conditioner  18 - 6 A and pin arrangement of a connector for the manual air conditioner  18 - 6 B are different from each other. 
     In order to cope with this change, a microcomputer  18 - 2   a  formed of an FPGA is mounted on the control box  18 - 2 , and a microcomputer  18 - 3   a  formed of an FPGA is also mounted on the control box  18 - 3 . The microcomputer  18 - 2   a  formed of an FPGA is mounted in main bodies or connectors of the automatic air conditioner  18 - 6 A and the manual air conditioner  18 - 6 B illustrated in  FIG. 18B . 
     Each connection destination is appropriately selected by the microcomputers  18 - 2   a  and  18 - 3   a  rewriting a program according to a specification for each circuit of the connected branch line sub-harnesses  18 - 4  and  18 - 5 . As illustrated in  FIG. 18B , a microcomputer disposed in a branch line sub-harness on an accessory side or a connector thereof performs controls so that a specification difference such as a connector pin arrangement difference is absorbed. Consequently, an accessory side can absorb a connection specification in a case where respective accessories are connected to the control boxes  18 - 2  and  18 - 3 , and a specification of the backbone side can be used in common. 
     &lt;Technique for Coping with Change in Connection Specification&gt; 
       FIG. 19  is a perspective view illustrating a connection example between a control box on a trunk line and branch line sub-harnesses. 
     A plurality of connectors  19 - 1   a ,  19 - 1   b ,  19 - 1   c ,  19 - 1   d ,  19 - 1   e  and  19 - 1   f  which have the same size or shape are disposed to be arranged side by side on a control box  19 - 1  illustrated in  FIG. 19  in order to connect various branch lines and accessories. In a case where an accessory is connected to the control box  19 - 1 , any one of the plurality of connectors  19 - 1   a  to  19 - 1   f  is selected, and branch line sub-harnesses  19 - 2 A,  19 - 2 B and  19 - 2 C are respectively connected. 
     Here, a worker can freely select a position of a connector which is a connection destination of each of the branch line sub-harnesses  19 - 2 A,  19 - 2 B, and  19 - 2 C as necessary when a vehicle is produced. A change in a position of a connector which is a connection destination of the branch line sub-harnesses  19 - 2 A,  19 - 2 B, and  19 - 2 C is coped with by automatically changing a circuit connection state in the control box  19 - 1  by a microcomputer formed of an FPGA built in the control box  19 - 1  rewriting a program. 
     Therefore, the worker can freely select a position of a connector which is a connection destination of each of the branch line sub-harnesses  19 - 2 A,  19 - 2 B, and  19 - 2 C, and thus productivity is improved. It is possible to reduce the number of components by using a function in common. 
     &lt;Technique of Using AC Power&gt; 
       FIG. 20  is a perspective view illustrating an arrangement example of a trunk line and a plurality of branch line sub-harnesses routed on a vehicle body. 
     An on-vehicle system illustrated in  FIG. 20  includes a backbone trunk line  20 - 1  routed linearly in a front-and-rear direction of a vehicle body, and a plurality of branch line sub-harnesses  20 - 2 A,  20 - 2 B and  20 - 2 C connected to respective locations of the backbone trunk line  20 - 1 . The respective branch line sub-harnesses  20 - 2 A,  20 - 2 B and  20 - 2 C are connected to control boxes provided on the backbone trunk line  20 - 1 . 
     As a characteristic matter, AC power is supplied to the backbone trunk line  20 - 1 . Specifically, a voltage of about AC 200 V is used. Each control box is provided with a transformer and an AC/DC converter, transforms the AC power and converts the AC power into a predetermined DC voltage in the control box, and then supplies to each of the branch line sub-harnesses  20 - 2 A,  20 - 2 B and  20 - 2 C. In the example illustrated in  FIG. 20 , DC power voltages such as DC 5 V, DC 48 V, and DC 12 V are respectively supplied to the branch line sub-harnesses  20 - 2 A,  20 - 2 B and  20 - 2 C. 
     As mentioned above, AC power is made to flow through the backbone trunk line  20 - 1 , and thus it is possible to reduce a power loss in the trunk line compared with a case of DC power. Since a configuration is simple, and a voltage can be converted by using a cheap transformer, it is possible to reduce cost of the system. A power loss is reduced, and thus fuel efficiency of a vehicle is improved. 
     &lt;Technique of Using Multiplex Communication&gt; 
       FIGS. 21A and 21B  are block diagrams illustrating a plurality of control boxes and a communication trunk line connecting the control boxes to each other. 
     In a configuration illustrated in  FIG. 21A , a communication line  21 - 3  of a backbone trunk line connecting two control box  21 - 1  and  21 - 2  to each other is formed of a set of a plurality of electric wires. In other words, individual communication lines of the same number of signals to be transmitted are required to be prepared in order to secure communication paths, and thus, if the number of signals increases, the number of communication lines also increases. 
     On the other hand, in the configuration illustrated in  FIG. 21B , a communication line  21 - 3 B of a backbone trunk line connecting two control box  21 - 1 B and  21 - 2 B to each other is formed of only one or two communication lines. 
     In other words, in a configuration illustrated in  FIG. 21B , since signals of a plurality of systems are superimposed on a single communication line by using a technique such as time division multiplexing (TDM), it is possible to considerably reduce the number of communication lines in a case where the number of signals to be transmitted increases. A technique such as frequency division multiplexing (FDM) may be used instead of time division multiplexing (TDM). 
     In a case where the number of communication lines is large as in  FIG. 21A , a communication line may be required to be divided at an intermediate portion of a line path of a trunk line, but a communication line is not required to be divided by reducing the number of communication lines, and thus a configuration can be simplified. Therefore, the number of circuits and the number of components are reduced. 
     &lt;Technique for Recovery During Occurrence of Abnormality&gt; 
       FIG. 22  is an electrical circuit diagram illustrating a configuration example of a control box having a recovery function. 
     Abnormality such as disconnection of a circuit may occur in a backbone trunk line or a control box. If such abnormality occurs, predetermined source power cannot be supplied to a branch line sub-harness or a load side, and thus operations of accessories including various loads are stopped. In order to prevent this, a recovery function is provided. 
     In the configuration illustrated in  FIG. 22 , a case is assumed in which source power supplied from a main power source  22 - 2  of a vehicle is supplied to two loads  22 - 3  and  22 - 4  via a control box  22 - 1 . If a switch  22 - 1   a  is closed, power can be supplied to the load  22 - 3 . If a switch  22 - 1   b  is closed, power can be supplied to the load  22 - 4 . 
     However, if a failure such as disconnection occurs in a line path connected to the switch  22 - 1   b , an abnormal state occurs in which power is not supplied to the load  22 - 4  even if the switch  22 - 1   b  is closed. Therefore, assuming that the load  22 - 4  is a load having considerably high priority, in the configuration illustrated in  FIG. 22 , a backup path  22 - 1   c  is connected in a state of in parallel to the path of the switch  22 - 1   b . The backup path  22 - 1   c  is connected to a relay  22 - 1   d  which can be turned on and off by a microcomputer  22 - 1   e.    
     If it is detected that abnormality has occurred in a conduction path of the switch  22 - 1   b , the microcomputer  22 - 1   e  automatically switches on the relay  22 - 1   d  so as to perform recovery control in which source power is supplied to the load  22 - 4  via the backup path  22 - 1   c . The microcomputer  22 - 1   e  controls a warning display portion provided in a meter unit of a vehicle to display the occurrence of the failure. The reliability regarding a wire harness and operations of various accessories is improved due to the recovery function. 
     &lt;Proximity Wireless Communication Technique on Vehicle&gt; 
       FIGS. 23A and 23B  are block diagrams illustrating connection examples between a wire harness and a load.  FIG. 24  is a perspective view illustrating a specific example of arrangement and connection of various constituent elements on a vehicle body. 
     As illustrated in  FIG. 23A , in a case where various accessories disposed in a door  23 - 3  of a vehicle are connected to a wire harness  23 - 1  on a vehicle interior side via a wire harness, an electric wire bundle at a bent part of the wire harness which is bent with opening and closing of the door generally is put in a grommet  23 - 2  and thus has functions such as protection of electric wires, waterproof, dustproof, and soundproof. However, in a case where a grommet is used, it is hard to perform routing work of a wire harness, and component cost also increases. 
     Therefore, in the configuration illustrated in  FIG. 23B , proximity wireless communication units  23 - 5  and  23 - 6  are used to connect a control box  23 - 4  on a backbone on the vehicle interior side to various accessories disposed in a door  23 - 7  of the vehicle. The proximity wireless communication units  23 - 5  and  23 - 6  has not only a communication function but also a function of supplying source power in a wireless manner. Therefore, in a case of using the configuration illustrated in  FIG. 23B , a grommet is not necessary, and routing work for connection of accessories is also considerably simplified. 
     A description will be made on a more realistic configuration example on a vehicle. In a configuration illustrated in  FIG. 24 , a backbone main line  24 - 1 , an instrument panel portion backbone  24 - 2 , an engine compartment backbone  24 - 3 , and the like are routed at respective locations on a vehicle body as trunk lines. Control boxes  24 - 41 ,  24 - 42 ,  24 - 43 ,  24 - 44  and  24 - 45  are disposed at respective locations in these trunk lines. 
     In the configuration illustrated in  FIG. 24 , a steering module  24 - 5  and the control box  24 - 41  are connected to each other in a wireless manner through proximity wireless communication. The respective control boxes and the accessories in the door are also connected to each other in a wireless manner through proximity wireless communication. Accessories such as a sensor  24 - 7  and an antenna  24 - 8  disposed in a luggage space and the control box  24 - 45  are also connected to each other in a wireless manner through proximity wireless communication. 
     &lt;Technique for Noise Countermeasure&gt; 
       FIGS. 25A, 25B and 25C  are block diagrams illustrating specific examples of connection states of a trunk line, a control box, a battery, and the like. 
     In a configuration example illustrated in  FIG. 25A , in the same manner as in a general vehicle, a single main battery  25 - 1  and an alternator  25 - 2  are connected to the vicinity of an end of a wire harness  25 - 3 . Various parts of the wire harness  25 - 3  are connected to accessories such as electronic control units (ECUs)  25 - 4  and  25 - 5 , and an electric motor  25 - 6 . 
     In the configuration as illustrated in  FIG. 25A , an apparatus such as the alternator  25 - 2  or the electric motor  25 - 6  is a source generating noise, and thus there is a probability that electromagnetic noise generated therefrom has an adverse effect on the electronic control units  25 - 4  and  25 - 5  or the like located in the vicinity thereof. 
     Therefore, the following countermeasures are taken in order to reduce the influence of noise. In other words, a plurality of batteries are prepared and disposed in a distribution manner in a backbone at positions close to the noise sources. Consequently, the battery easily absorbs generated noise. It is possible to prevent sneaking of noise into each electronic control unit. The noise problem can be solved regardless of locations on the backbone where noise sources and apparatuses which are easily influenced by noise are connected. 
     In the configuration example illustrated in  FIG. 25B , in addition to the main battery  25 - 1 , sub-batteries  25 - 1 B and  25 - 1 C are connected to the backbone of the wire harness  25 - 3  in a distribution manner. Therefore, noise generated from the electric motor  25 - 6  which is a noise source is absorbed by the sub-batteries  25 - 1 B and  25 - 1 C connected in the vicinity thereof. 
     The electronic control units  25 - 4  and  25 - 5  which are easily influenced by noise are disposed at positions farther away from the noise source than the sub-batteries  25 - 1 B and  25 - 1 C, and are thus hardly influenced by noise. 
     In the configuration example illustrated in  FIG. 25C , in addition to the main battery  25 - 1 , six sub-batteries  25 - 1 B,  25 - 1 C,  25 - 1 D,  25 - 1 E,  25 - 1 F and  25 - 1 G are connected to the backbone of the wire harness  25 - 3  in a distribution manner. The sub-battery  25 - 1 B is connected to a trunk line  25 - 3 A between the main battery  25 - 1  and a control box  25 - 7 A. The sub-battery  25 - 1 C is connected to an internal circuit of the control box  25 - 7 A. 
     The sub-battery  25 - 1 D is connected to a trunk line  25 - 3 B between two control boxes  25 - 7 A and  25 - 7 B. The sub-battery  25 - 1 E is connected to an internal circuit of the control box  25 - 7 B. The sub-battery  25 - 1 F is connected to a trunk line  25 - 3 C between two control boxes  25 - 7 B and  25 - 7 C. The sub-battery  25 - 1 G is connected to an internal circuit of the control box  25 - 7 C. 
     As in the configuration illustrated in  FIG. 25C , in a case where a plurality of sub-batteries are connected, each sub-battery may be connected to any location. Since each sub-battery functions as a noise filter, a plurality of sub-batteries are connected, and thus performance of absorbing noise in a power supply line is improved. 
     &lt;Technique for Noise Countermeasure&gt; 
       FIGS. 26A, 26B, 26C, 26D and 26E  are block diagrams illustrating specific examples of connection states of a trunk line and one or more batteries. 
     In this technique, countermeasures of the following (1), (2) and (3) are taken. 
     (1) A battery having a characteristic of absorbing noise is configured to be connected to any location of a backbone trunk line. (2) In order to remove the influence of a voltage fluctuation or noise, a low impedance routing material is used as a routing material of a backbone trunk line. (3) A configuration of a backbone trunk line is used in common, and a battery attachment position can be changed according to conditions of each vehicle. 
     In a configuration illustrated in  FIG. 26A , control boxes  26 - 4 A,  26 - 4 B,  26 - 4 C and  26 - 4 D are respectively connected to four ends of a backbone trunk line  26 - 3 . A main battery  26 - 1  is connected to the backbone trunk line  26 - 3  at the position of the control box  26 - 4 A, and a sub-battery  26 - 2  is connected to the backbone trunk line  26 - 3  at the position of the control box  26 - 4 D. Even in a case where the main battery  26 - 1  and the sub-battery  26 - 2  are connected to the backbone trunk line  26 - 3  at any positions of the control boxes  26 - 4 A,  26 - 4 B,  26 - 4 C and  26 - 4 D, the backbone trunk line  26 - 3  whose configuration is used in common can be used. 
     In a configuration illustrated in  FIG. 26B , only a main battery  26 - 1  is connected to a tip end of a backbone trunk line  26 - 3  located on the front side of a vehicle via a control box  26 - 4 A. 
     In a configuration illustrated in  FIG. 26C , only a sub-battery  26 - 2  is connected to a rear end of a backbone trunk line  26 - 3  located on the rear side of a vehicle via a control box  26 - 4 D. 
     In a configuration illustrated in  FIG. 26D , a main battery  26 - 1  is connected to a tip end of a backbone trunk line  26 - 3  located on the front side of a vehicle via a control box  26 - 4 A, and a sub-battery  26 - 2  is connected to a rear end of a backbone trunk line  26 - 3  located on the rear side of a vehicle via a control box  26 - 4 D. 
     In a configuration illustrated in  FIG. 26E , a sub-battery  26 - 2  is disposed in the vicinity of the center of a vehicle, and the sub-battery  26 - 2  is directly connected to the center of a backbone trunk line  26 - 3 . 
     &lt;Technique for Noise Countermeasure&gt; 
       FIG. 27  is a block diagram illustrating a specific example of a connection state of a trunk line and a plurality of batteries. 
     In a configuration illustrated in  FIG. 27 , control boxes  27 - 2 ,  27 - 3 ,  27 - 4  and  27 - 5  are respectively connected to four ends of a backbone trunk line  27 - 1 . Each of the plurality of control boxes  27 - 2 ,  27 - 3 ,  27 - 4  and  27 - 5  has a small-sized sub-battery (secondary battery) built therein. Each sub-battery is connected to a power source line of the backbone trunk line  27 - 1 . A main power source such as a main battery (not illustrated) is also connected to the backbone trunk line  27 - 1 . Therefore, the content shown in the following (1) to (4) is realized. 
     (1) A plurality of batteries can be disposed at respective parts of the backbone trunk line  27 - 1  in a distribution manner. Consequently, a voltage fluctuation in a case where a voltage required in a load is high can be suppressed by supplying a current from each battery. 
     (2) A plurality of batteries disposed can be normally connected to respective portions of the backbone trunk line  27 - 1  in a distribution manner. Consequently, in a case where regenerative electrical energy appears on the backbone trunk line  27 - 1 , this energy can be efficiently recovered by a plurality of batteries at the respective parts. Therefore, a recovery ratio of regenerative energy is improved. 
     (3) Since a plurality of batteries are provided, in a case where abnormality occurs in a main power source such as a main battery, backup power can be supplied from a plurality of sub-batteries. Such power backup control can be automatically performed by using microcomputers provided in the control boxes  27 - 2 ,  27 - 3 ,  27 - 4  and  27 - 5 . 
     (4) Since a battery is provided in each area on a vehicle, even in a case where a part of the backbone trunk line  27 - 1  is disconnected due to vehicle crash or the like, source power can be supplied from a battery located in the vicinity of an area in which an accessory is disposed, and thus a safe power source which does not stop supplying power can be implemented. 
     &lt;Technique for Noise Countermeasure&gt; 
       FIG. 28  is an electrical circuit diagram illustrating a configuration example of a power source system in an on-vehicle system. 
     A device illustrated in  FIG. 28  includes an alternator  28 - 1 , a main battery  28 - 2 , a backbone trunk line  28 - 3 , a body ground  28 - 4 , accessories  28 - 5 A to  28 - 5 D, and branch line sub-harnesses  28 - 6 A to  28 - 6 D. The backbone trunk line  28 - 3  includes a power source line  28 - 3   a  and a ground (GND) line  28 - 3   b . The body ground  28 - 4  is a ground path using a metal forming a body of a vehicle. 
     In a configuration illustrated in  FIG. 28 , the alternator  28 - 1  and the main battery  28 - 2  are connected to an upstream side of the backbone trunk line  28 - 3 . Respective parts of the backbone trunk line  28 - 3  are connected to the accessories  28 - 5 A to  28 - 5 D via the branch line sub-harnesses  28 - 6 A to  28 - 6 D. 
     Each negative terminal of the alternator  28 - 1  and the main battery  28 - 2  is respectively connected to both of the earth line  28 - 3   b  of the backbone trunk line  28 - 3  and the body ground  28 - 4 . Terminals on a ground side of a power source of the accessories  28 - 5 A and  28 - 5 B are connected to only the earth line  28 - 3   b  of the backbone trunk line  28 - 3  via the branch line sub-harnesses  28 - 6 A and  28 - 6 B, respectively. Terminals on a ground side of a power source of the accessories  28 - 5 C and  28 - 5 D are connected to only the body ground  28 - 4  via a dedicated earth line or a casing ground. 
     A resistance value of a line path in a case of using the body ground  28 - 4  is very small as, for example, about 0.7 mΩ, but a resistance value relatively increases in a case of using the earth line  28 - 3   b  of the backbone trunk line  28 - 3 . 
     Since the earth line  28 - 3   b  of the backbone trunk line  28 - 3  has a relatively large resistance value, if a large current flows, a ground potential fluctuation may occur due to a voltage drop caused by a resistance of the line path. However, if the body ground  28 - 4  is used, a resistance value thereof is small, and thus a ground potential fluctuation scarcely occurs. 
     In the configuration illustrated in  FIG. 28 , since it is assumed that a power source current consumed in the accessories  28 - 5 A and  28 - 5 B is relatively small, the ground terminals thereof are connected to the earth line  28 - 3   b  of the backbone trunk line  28 - 3 . In addition, since it is assumed that a power source current consumed in the accessories  28 - 5 C and  28 - 5 D is relatively large, the ground terminals thereof are connected to the body ground  28 - 4 . In the above-described connection way, it is possible to reduce a ground potential fluctuation. 
     The alternator  28 - 1  has a switching circuit such as a DC/DC converter built therein, and thus there is a high probability that noise is generated due to switching. However, as illustrated in  FIG. 28 , the negative terminal of the alternator  28 - 1  is connected to the body ground  28 - 4 , and thus generated noise can be absorbed by using the main battery  28 - 2  or the like since resistance of a line path is small. 
     &lt;Technique for Communicating Between Vehicle and Vehicle Exterior&gt; 
       FIG. 29A  is a block diagram illustrating a configuration example of an on-vehicle system, and  FIG. 29B  is a perspective view illustrating an example of an exterior of the same on-vehicle system. 
     The on-vehicle system illustrated in  FIG. 29B  includes a plurality of control boxes  29 - 1 , a backbone trunk line  29 - 4  connecting the control boxes to each other, and a plurality of branch line sub-harnesses  29 - 5  connected to the backbone trunk line  29 - 4  via the control boxes. 
     As illustrated in  FIG. 29A , accessories  29 - 3 A and  29 - 3 B, and the like are connected to and under the control of the branch line sub-harnesses  29 - 5 . As specific examples of the accessories  29 - 3 A and  29 - 3 B, for example, an audio device or an electronic control unit (ECU) is connected. As illustrated in  FIG. 29B , in this example, a data communication module (DCM)  29 - 1   a  is provided in one of the plurality of control boxes  29 - 1 . 
     In a general vehicle, respective accessories are separately connected to the DCM so that the accessories of various kinds perform wireless communication with a vehicle exterior. Thus, connection locations of various circuits concentrate on the DCM. If many circuits concentrate, the number of processed electric wires in a wire harness increases, which leads to an increase in a size of a connector, and thus productivity of the wire harness deteriorates. 
     Therefore, as in the configuration illustrated in  FIG. 29A , the DCM  29 - 1   a  is built in a single control box  29 - 1 , and the various accessories  29 - 3 A and  29 - 3 B are connected to the common control box  29 - 1 . 
     Since the control box  29 - 1  illustrated in  FIG. 29A  is connected to the backbone trunk line  29 - 4 , various kinds of accessories disposed at various positions on a vehicle are connected to the backbone trunk line  29 - 4 , and thus it is possible to easily use the wireless communication function of the DCM  29 - 1   a  via the trunk line. Consequently, it is possible to reduce the number of circuits of a wire harness, and thus to reduce component cost and manufacturing cost of the wire harness. 
     &lt;Technique Regarding Voltage and Current Consumption in Trunk Line&gt; 
       FIGS. 30A and 30B  are longitudinal sectional views respectively illustrating configuration examples of different backbone trunk lines.  FIG. 31  is a time chart illustrating an example of a correspondence relationship between a power source current and a power source voltage in a case where special power source control is performed. 
     In an on-vehicle system, if current consumption of an accessory connected to a wire harness increases, a voltage drop increases and a ground potential easily fluctuates in a case where resistance of an earth line is large. A ground terminal of the accessory may float from an earth line. There is a case where a power source voltage supplied to an accessory is reduced due to a voltage drop in a power source line. 
     Therefore, in the present embodiment, two kinds of power source voltages, for example, +12 V and +48 V are configured to be used together in a common backbone trunk line, and the two kinds of power source voltages are used depending on situations. 
     A backbone trunk line  30 - 1  illustrated in  FIGS. 30A and 30B  includes two power source lines  30 - 1   a  and  30 - 1   b , an earth line  30 - 1   c , and a communication line  30 - 1   d . In the present embodiment, it is possible to switch between power source voltages supplied to at least one of the power source lines  30 - 1   a  and  30 - 1   b . In other words, in a case where the power source voltage of +12 V is selected, as illustrated in  FIG. 30A , the power source voltage of +12 V is supplied to the power source line  30 - 1   a  or  30 - 1   b . In a case where the power source voltage of +48 V is selected, as illustrated in  FIG. 30B , the power source voltage of +48 V is supplied to the power source line  30 - 1   a  or  30 - 1   b.    
     For example, DC power supplied from a main power source such as a main battery is stepped up or down in a control box disposed on the backbone trunk line  30 - 1 , and thus switching between +12 V and +48 V can be performed. 
     Control is performed by using a microcomputer of the control box, and thus switching between +12 V and +48 V can be automatically performed. For example, if the microcomputer monitors a current required in a load or actual current consumption, automatic switching between voltages can be performed as in the example illustrated in  FIG. 31  depending on the magnitude of the current. 
     In other words, in a case where current consumption of a load is great, a voltage supplied by the control box is changed from +12 V to +48 V, and thus it is possible to reduce the influence of a decrease in a voltage supplied to the load. 
     &lt;Technique Regarding Configuration of Trunk Line&gt; 
       FIGS. 32A, 32B and 32C  are longitudinal sectional views respectively illustrating configuration examples of different backbone trunk lines. 
     In a general vehicle, +12 V is used as a power source voltage. However, if current consumption of a load increases, a problem such as a voltage drop in a wire harness occurs. If an electric wire diameter of the wire harness is increased in order to reduce the voltage drop, the wire harness grows too large, and thus a weight thereof also increases. 
     Therefore, as a power source voltage handled in a wire harness, +48 V is configured to be also used in addition to +12 V. 
     In a configuration illustrated in  FIG. 32A , a backbone trunk line is formed of four routing materials (electric wires, bus bars, and the like). Two of the four routing materials are used as a power source line and an earth (GND) line for +12 V, and the other two remaining routing materials are used as a power source line and an earth line for +48 V. 
     In a configuration illustrated in  FIG. 32B , a backbone trunk line is formed of three routing materials. One of the three routing materials is used as a power source line for +12 V, another one is used as an earth (GND) line, and the remaining one is used as a power source line for +48 V. 
     In a configuration illustrated in  FIG. 32C , a backbone trunk line is formed of two routing materials. One of the two routing materials is used as a common power source line for +12 V or +48 V, and the other one is used as an earth (GND) line. In a case of using the configuration illustrated in  FIG. 32C , for example, voltage switching between +12 V and +48 V is performed in a control box on the backbone trunk line. 
     &lt;Technique Regarding Power Saving Control&gt; 
     For example, if the supply of power to a load having low priority is reduced, or conduction of a load having low priority is temporarily stopped, power consumption of the entire vehicle can be reduced, and this leads to improvement of power efficiency and miniaturization of a battery. However, if such power saving control is performed at all times, a user may not be able to comfortably use a load having low priority. 
     Therefore, a case is assumed in which a normal mode is switched to a power saving mode only when a certain situation occurs, and the above-described power saving control is performed. Here, it is important how to define a determination condition for determining whether or not to switch the normal mode to the power saving mode. 
     In the present embodiment, past data DA and expectation data DB for one day from now on are prepared in order to determine the switching from the normal mode to the power saving mode. The past data DA is compared with the expectation data DB, a today&#39;s power use prediction is presented to a user, and a control device on a vehicle side automatically selects the power saving mode. 
     As a specific example of the past data DA, condition patterns such as a day basis, a season basis, and an environmental condition basis, for example, weather, temperature, and humidity are taken into consideration, and a power use amount for each condition pattern is measured, and is generated as data. The data is optimized by using a learning function. 
     As a specific example of the expectation data DB, there are use amount prediction data of a car air conditioner based on a today&#39;s weather prediction, a user&#39;s schedule data registered in a smart phone or the like, destination information which is input to a car navigation device, and the like. Specific condition patterns are extracted on the basis of the specific data, and thus appropriate expectation data DB can be obtained. 
     &lt;Technique for Preventing Battery Exhaustion&gt; 
     For example, in a case where a vehicle is parked without being connected to an external power source, most of the accessories on a vehicle are in a stop state, and power accumulated in a battery is scarcely consumed. However, for example, since some loads such as a theft prevention device continue to consume power even during parking, if a parking state is continued for a long period of time, battery exhaustion occurs, and thus the vehicle cannot be started. 
     Therefore, in the present embodiment, a control device on the vehicle performs special control in order to prevent battery exhaustion in advance. In other words, the control device recognizes a power residual capacity in a power source such as a main battery, measures a conduction current or a dark current flowing out of the battery, and predicts the number of days left until battery exhaustion occurs based on the information. In a case where the number of days left is small, the supply of power from the battery is automatically stopped. The supply of power may be controlled to be reduced stepwise. 
     &lt;Technique Regarding Disconnection Detection&gt; 
       FIG. 33  is an electrical circuit diagram illustrating a configuration example of a power source system in an on-vehicle system. 
     In an on-vehicle system illustrated in  FIG. 33 , an alternator  33 - 1  and a main battery  33 - 2  which are main power sources are connected to a tip end side of a backbone trunk line  33 - 4 , and a sub-battery  33 - 2 B is connected to a rear end side of the backbone trunk line  33 - 4  via a switch  33 - 5 . 
     A plurality of control boxes  33 - 3 A,  33 - 3 B and  33 - 3 C are connected to an intermediate portion of the backbone trunk line  33 - 4  in a distribution manner at respective positions. A power source line and an earth line are included as constituent elements of the backbone trunk line  33 - 4 . The power source line of the backbone trunk line  33 - 4  is configured to be used not only for the supply of power but also for communication. In other words, by using the existing power line communication (PLC) technique, DC source power and an AC signal for communication are transmitted in a state of being superimposed with each other on the power source line. 
     Therefore, each of the plurality of control boxes  33 - 3 A,  33 - 3 B and  33 - 3 C has an interface for PLC communication built therein, and thus the plurality of control boxes  33 - 3 A,  33 - 3 B and  33 - 3 C can perform PLC communication with each other. 
     In this configuration, for example, if the backbone trunk line  33 - 4  between the two control boxes  33 - 3 A and  33 - 3 B is disconnected, PLC communication cannot be performed between the two control boxes  33 - 3 A and  33 - 3 B. Therefore, in a case where the PLC communication cannot be performed, the control boxes  33 - 3 A and  33 - 3 B can recognize disconnection of the backbone trunk line  33 - 4 . Further, a position where the disconnection occurs can be specified. Each of the plurality of control boxes  33 - 3 A,  33 - 3 B and  33 - 3 C has a short-range wireless communication function so as to perform communication even in a case where the backbone trunk line  33 - 4  is disconnected. 
     In a case where the above-described disconnection occurs, power recovery control is performed according to a fail-safe function of any one of the control boxes  33 - 3 A,  33 - 3 B and  33 - 3 C which detected the disconnection. In other words, if the switch  33 - 5  is closed, source power is supplied to the backbone trunk line  33 - 4  from both of the main battery  33 - 2  and the sub-battery  33 - 2 B. The switch  33 - 5  is maintained in a closed state. Consequently, power is supplied to each circuit from the main battery  33 - 2  on the upstream side of the disconnection position, and power is supplied to each circuit from the sub-battery  33 - 2 B on the downstream side of the disconnection position. In a case where disconnection occurs, PLC communication is stopped, and communication paths between the control boxes  33 - 3 A,  33 - 3 B and  33 - 3 C are secured by using wireless communication whose function is restricted. 
     &lt;Technique for Using Communication System in Common&gt; 
       FIG. 34  is a longitudinal sectional view illustrating a configuration example of a communication cable. 
     There is a plurality of standards such as CAN or CXPI as standards related to communication on a vehicle. Therefore, there is a probability that communication interfaces based on a plurality of standards may be combined with each other due to a difference between vehicle specifications, a difference between areas on a vehicle, a difference between grades, and the like. Components such as communication cables having different configurations for the respective standards are used. Since the configurations are different from each other, components based on a plurality of standards cannot be used in common. 
     A communication cable  34 - 1  illustrated in  FIG. 34  is configured to be able to be used for both of communication based on the CAN standard and communication based on the CXPI standard. The communication cable  34 - 1  is formed of four electric wires including a power source line  34 - 1   a , an earth (GND) line  34 - 1   b , a high-side communication line  34 - 1   c , and a low-side communication line  34 - 1   d.    
     In a case of performing communication based on the CAN standard, both of the high-side communication line  34 - 1   c  and the low-side communication line  34 - 1   d  are used, and, in a case of performing communication based on the CXPI standard, only the high-side communication line  34 - 1   c  is used. Consequently, the communication cable  34 - 1  whose configuration is used in common can be used regardless of whether being connected to a communication interface based on any one of the CAN and CXPI standards. Through this common use, manufacturing of a wire harness is facilitated, and thus various accessories are also easily post-installed. 
     A configuration of a switching circuit CB 11  for switching between two kinds of interface connections based on CAN and CXPI is illustrated in  FIG. 10  as described above. 
     &lt;Technique for Using Configuration in Common&gt; 
       FIG. 35  is a block diagram illustrating a configuration example of a communication system in an on-vehicle system. 
     For example, in a case where various accessories are connected to and under the control of the control boxes  31  to  33  as illustrated in  FIG. 1  via branch line sub-harnesses, it is hard to use a large-sized control box, and the number of connectors for connection of the branch line sub-harnesses may be restricted. Thus, in a case where a plurality of accessories are to be connected to a single control box, the number of connectors may be insufficient. In other words, a width of the control box is small, and thus there is a case where a plurality of connectors cannot be provided in the control box. 
     Therefore, in the present embodiment, a modular connection connector (JC)  35 - 1  illustrated in  FIG. 35  is prepared. The modular connection connector  35 - 1  has a configuration similar to that of a table tap, an upstream side thereof is connected to a single branch line sub-harness  35 - 5 , and a connection portion  35 - 1   a  on a downstream side is provided with a plurality of connectors for connection of a plurality of apparatuses. 
     As illustrated in  FIG. 35 , the branch line sub-harness  35 - 5  of the modular connection connector  35 - 1  is connected to a connector of a single control box  35 - 2 C as a branch line, for example. As illustrated in  FIG. 35 , the modular connection connector  35 - 1  is provided with two PHY circuits, a network switch (switch), a gateway (GW), a processing unit, an CAN-FD interface, a CXPI interface, a standard function driver, and the like therein. 
     In the configuration illustrated in  FIG. 35 , one of the PHY circuits of the modular connection connector  35 - 1  is connected to an apparatus  35 - 7  of a camera and a sensor system via a communication line  35 - 8 . Two loads are connected to and under the control of the standard function driver. 
     The connection portion  35 - 1   a  on the downstream side of the modular connection connector  35 - 1  is provided with a plurality of connectors, and thus a plurality of accessories can be connected thereto as necessary. For example, as illustrated in  FIG. 35 , a DCM and an antenna may be connected, or a load  6  may be connected via an electronic control unit (ECU). Instead of the ECU, a load may also be connected via connectors (E connectors) having a simple communication function or an output control function. 
     Another modular connection connector  35 - 1  can be connected in series to the connection portion  35 - 1   a  on the downstream side of the modular connection connector  35 - 1 , and thus it is possible to increase the number of connectable apparatuses as necessary. Constituent elements such as an ECU box  35 - 3  illustrated in  FIG. 35  will be described later in detail. 
     &lt;Technique of Incorporating Optical Communication Path in Backbone Trunk Line&gt; 
     As illustrated in  FIG. 10  described above, optical fiber cables are used as two communication lines L 4 B and L 5 B of the backbone trunk line BB_LM, and thus the control box CB has an optical communication function. Consequently, since large-capacity or high-speed communication can be performed by using the trunk line, it can be used for communication for a high grade vehicle. Specifically, since the maximum communication speed of about 10 Gbps can be ensured, it can be applied also to an application in which high resolution video data is required to be sent without time lag. 
     &lt;Technique for Handling Optical Signal in Control Box&gt; 
     A function for handling an optical signal is installed in a control box. For example, as in the on-vehicle system illustrated in  FIG. 10 , the PHY circuits CB 03  and CB 04  are incorporated into the control box CB, so that an electrical signal can be converted into an optical signal so as to be transmitted, and a received optical signal can be converted into an electrical signal so as to be subjected to a reception process. 
     More specifically, as in the control box CB( 1 ) illustrated in  FIG. 57 , the optical/electrical conversion units  57 - 2  and  57 - 3 , and the electrical/optical conversion units  57 - 10  and  57 - 11  are incorporated therein, and thus mutual conversion between an optical signal and an electrical signal can be performed. 
     &lt;Technique Regarding Connection Form of Communication System Trunk Line&gt; 
       FIG. 36  is a block diagram illustrating a configuration example of communication systems in an on-vehicle system in which the communication systems are connected in a ring form.  FIG. 37  is a block diagram illustrating a configuration example of communication systems in an on-vehicle system in which the communication systems are connected in a star form. 
     In the on-vehicle system illustrated in  FIG. 36 , four control boxes  36 - 1 ,  36 - 2 ,  36 - 3  and  36 - 4  are connected to each other via a communication trunk line  36 - 5  of a backbone, and this connection form is configured in a ring shape. 
     In other words, a signal transmitted from the control box  36 - 1  reaches the next control box  36 - 2  via the communication trunk line  36 - 5 , and the signal relayed inside the control box  36 - 2  is transmitted from the control box  36 - 2  to the communication trunk line  36 - 5  and reaches the next control box  36 - 3 . Similarly, the signal which is received and relayed by the control box  36 - 3  is transmitted to the communication trunk line  36 - 5 , and reaches the next control box  36 - 4 . The signal which is received and relayed by the control box  36 - 4  is transmitted to the communication trunk line  36 - 5 , and reaches the next control box  36 - 1 . In the above-described way, the signal on the communication trunk line  36 - 5  is sequentially transmitted while being relayed along the ring-shaped path. 
     Therefore, the same communication function as that of the on-vehicle system illustrated in  FIG. 6  can be realized. If a path of the communication trunk line  36 - 5  is duplicated, even in a case where abnormality occurs in one communication path, a communication path can be secured by using the remaining normal path, and thus reliability is increased. A communication speed can be doubled by using the two paths together. 
     On the other hand, in the on-vehicle system illustrated in  FIG. 37 , five control boxes  37 - 1 ,  37 - 2 ,  37 - 3 ,  37 - 4  and  37 - 5  are connected to communication trunk lines  37 - 5   a  and  37 - 5   b , and this connection form is configured in a star shape. In other words, the single control box  37 - 1  is centered, and the other four control boxes  37 - 2  to  37 - 5  are connected thereto via separate paths. 
     In the configuration illustrated in  FIG. 37 , each communication path is duplicated. For example, the control box  37 - 1  and the control box  37 - 3  are connected to each other via the two communication trunk lines  37 - 5   a  and  37 - 5   b  which are independent from each other. 
     Each of the duplicated communication paths may be used separately depending on, for example, priority, importance, and a security level difference of communication. Specifically, a communication path having high priority is used for communication related to traveling of a vehicle, and a communication path having low priority is used for other general communication. In a case where a communication failure occurs, one of duplicated communication paths may be used as a backup path. A security level may be divided into, for example, private and public. 
     The control box  37 - 1  at the center of the star shape selectively determines a transmission destination of a packet to be transmitted next from among the four control boxes  37 - 2  to  37 - 5 , and determines a communication path along which the packet is to be transmitted of the communication paths of two systems. 
     When determining the priority in communication for the on-vehicle system, the priority is generally determined in advance for each component, and thus information handled by, for example, an engine ECU is treated as information having high priority. However, actually, there are many cases where information having low priority is handled by the engine ECU. 
     Therefore, an ID indicating importance is given to each piece of information, the importance of information is identified on the basis of the ID, and a communication path is automatically selected. In other words, information having high importance is transmitted along the communication trunk line  37 - 5   a  of the duplicate communication trunk lines  37 - 5  of the backbone, and information having low importance is transmitted along the communication trunk line  37 - 5   b  thereof. 
     &lt;Technique Using Wireless Communication in System on Vehicle&gt; 
       FIGS. 38A, 38B and 38C  illustrate communication connection states between apparatuses in different situations, in which  FIG. 38A  is a perspective view, and  FIGS. 38B and 38C  are block diagrams. 
     For example, in a case where a communication line is included in a backbone trunk line  38 - 1  illustrated in  FIG. 38A , wired communication can be performed between a plurality of control boxes  38 - 2  and  38 - 3  connected to the backbone trunk line  38 - 1 . However, the backbone trunk line  38 - 1  may be damaged during vehicle crash or the like, and thus the communication line may be disconnected. 
     Therefore, in order to provide redundancy to a communication path, a short-range wireless communication function is installed in each of the control boxes  38 - 2  and  38 - 3 . Consequently, in a configuration illustrated in  FIG. 38A , even in a case where the communication line between the control boxes  38 - 2  and  38 - 3  is disconnected, a communication path between the plurality of control boxes  38 - 2  and  38 - 3  can be secured via a wireless communication line. In a location where disconnection does not occur, a communication path between the control boxes is secured via the communication line of the backbone trunk line  38 - 1 . 
     As illustrated in  FIG. 38B , even in a case where a communication line between control boxes  38 - 4  and  38 - 5  is disconnected, and a communication line between control boxes  38 - 5  and  38 - 6  is also disconnected, communication paths can be secured by using wireless communication. Therefore, as illustrated in  FIG. 38C , communication can be performed between the control boxes  38 - 4  and  38 - 5 , between the control boxes  38 - 5  and  38 - 6 , and between control boxes  38 - 4  and  38 - 6 . Consequently, reliability of a communication path can be secured. 
     &lt;Technique Regarding Diameter Reduction of Backbone Trunk Line&gt; 
       FIG. 39  is an electrical circuit diagram illustrating a configuration example of a power source system in an on-vehicle system. 
     In the on-vehicle system illustrated in  FIG. 39 , an alternator (generator: ALT)  39 - 1  is connected to one end (for example, a front side in a vehicle body) of a backbone trunk line  39 - 3 , and a main battery  39 - 2  is connected to the other end (for example, a rear side in the vehicle body) of the backbone trunk line  39 - 3 . 
     Loads  39 - 4 A,  39 - 4 B and  39 - 4 C are connected to respective locations of an intermediate portion of the backbone trunk line  39 - 3  via predetermined branch line sub-harnesses. In  FIG. 39 , voltages of the backbone trunk line  39 - 3  at the respective connection locations of the loads  39 - 4 A,  39 - 4 B and  39 - 4 C are indicated by V 1 , V 2  and V 3 . 
     Typically, a DC output voltage of the alternator  39 - 1  is higher than a voltage between terminals of the main battery  39 - 2 . Therefore, as illustrated in  FIG. 39 , a relationship of “V 1 &gt;V 2 &gt;V 3 ” is satisfied. 
     In the configuration illustrated in  FIG. 39 , a power source current flowing through each load  39 - 4 A,  39 - 4 B and  39 - 4 C can flow from the alternator  39 - 1  toward a right side of the backbone trunk line  39 - 3 , or can flow from the main battery  39 - 2  to a left side of the backbone trunk line  39 - 3 . 
     Therefore, even in a case where power is supplied to a load requiring a large current from both of the alternator  39 - 1  and the main battery  39 - 2 , it is possible to prevent concentration of the current on the same location on the backbone trunk line  39 - 3  since a current from the alternator  39 - 1  and a current from the main battery  39 - 2  pass through different locations. As a result, the maximum rated value of a current flowing through each portion of the backbone trunk line  39 - 3  is reduced, and thus it is possible to reduce a diameter of a bus bar or the like of a power source line of the backbone trunk line  39 - 3 . 
     &lt;Technique Regarding Arrangement Form of a Plurality of Loads&gt; 
       FIG. 40  is an electrical circuit diagram illustrating a configuration example of a power source system in an on-vehicle system. 
     In the on-vehicle system illustrated in  FIG. 40 , a backbone trunk line  40 - 3  is linearly routed from an engine compartment (engine room) region  40 - 2  of a vehicle body to a vehicle interior region  40 - 1 . The backbone trunk line  40 - 3  is connected to an alternator (ALT)  40 - 4  which is a main power source, and a power source  40 - 5  formed of a main battery. 
     Various kinds of loads  40 - 6 A,  40 - 6 B,  40 - 6 C and  40 - 6 D on a vehicle are connected to respective portions on the backbone trunk line  40 - 3  via predetermined branch line sub-harnesses. 
     In this example, the load  40 - 6 A consumes large power. The load  40 - 6 B consumes small power, such as an ECU, a switch, a sensor, or an illumination. The load  40 - 6 C consumes intermediate power, such as a lamp, or an electric motor provided in a body system. The load  40 - 6 D consumes large power, such as an electric motor provided in a chassis system. 
     As illustrated in  FIG. 40 , in this configuration, the small-power load  40 - 6 B is connected to a position close to the power source  40 - 5 , and the large-power load  40 - 6 D is connected to a position far away from the power source  40 - 5 . Each load is connected on the basis of this positional relationship, and thus it is possible to reduce a voltage drop at an end of the backbone trunk line  40 - 3 . 
     &lt;Technique Regarding Prevention of Illegal Apparatus Connection&gt; 
     In a case where versatile connection ports for connection of various apparatuses, for example, connection ports based on a USB standard are present in the above-described control box CB or the like more than necessary, an illegal apparatus may be connected to an unoccupied port which is not used among the connection ports. For example, a third party may intrude into a vehicle when a user of the vehicle does not aware thereof, and connects an illegal apparatus to an unoccupied port. 
     Therefore, a function of preventing an intruder from connecting an illegal apparatus to an unoccupied port is provided. Specifically, an intrusion sensor is mounted on a vehicle, and an action is taken so that an illegally connected apparatus is not operated under the control of a microcomputer provided in the control box CB or the like when the intrusion is detected. In other words, the microcomputer performs control so that a power source and a communication line corresponding to an unoccupied port are automatically interrupted. 
     The microcomputer can identify whether a port is in use or is an unoccupied port, for example, by monitoring a conduction current for each port. Connection verification of each connection port is performed whenever an ignition switch of a vehicle is turned on, and thus it is possible to identify whether or not the port is in use. 
     &lt;Technique Regarding Backup and Fuse of Power Source&gt; 
       FIG. 41  is an electrical circuit diagram illustrating a configuration example of a backup power source circuit. 
     A backup power source circuit  41 - 1  illustrated in  FIG. 41  is provided in the control box CB, and may be used to supply power to most kinds of accessories. As illustrated in  FIG. 41 , the circuit is provided with a main power source line  41 - 2 , a sub-power source line  41 - 3 , two switching elements  41 - 5 , two diodes  41 - 6 , a power source output portion  41 - 7 , and an earth line  41 - 9 . The power source output portion  41 - 7  is connected to a part of a connector  41 - 8  of the control box CB provided for connection of a predetermined branch line sub-harness. 
     The connector  41 - 8  is provided with four terminals  41 - 8   a ,  41 - 8   b ,  41 - 8   c  and  41 - 8   d . The terminals  41 - 8   a  and  41 - 8   d  are respectively connected to an earth (GND) line and a power source line of the power source output portion  41 - 7 . The terminals  41 - 8   b  and  41 - 8   c  are connected to two communication lines. The respective sizes of the terminals  41 - 8   a ,  41 - 8   b ,  41 - 8   c  and  41 - 8   d  are assumed to be 1.5, 0.5, 0.5, and 1.5. 
     DC power from a main battery or the like of a vehicle is supplied to the main power source line  41 - 2  of the backup power source circuit  41 - 1  via a backbone trunk line. DC power from a predetermined sub-battery or the like is supplied to the sub-power source line  41 - 3  via the backbone trunk line or the like. Power from a high-voltage battery pack used to drive a vehicle may be stepped down by a DC/DC converter so as to be supplied to at least one of the sub-power source line and the main power source line of the backbone trunk line as sub-power. 
     A control signal  41 - 4  for controlling turning-on and turning-off of the two switching elements  41 - 5  is supplied from a microcomputer (not illustrated) provided in the control box CB. The microcomputer appropriately controls the control signal  41 - 4 , and can thus realize functions shown in the following (1), (2) and (3). 
     (1) Electronic fuse function: The magnitude of a load current is monitored, and a conduction path is automatically disconnected in a case where conduction of an excessive current of a predetermined level or higher is detected. The conduction path is connected again in a case where returning of a normal state is detected. 
     (2) Automatic switching function between main power source and sub-power source: For example, power is supplied to a load side only from the main power source line  41 - 2  side during normal times, and switching automatically occurs so that power is supplied to the load from the sub-power source line  41 - 3  side in a case where a failure or the like of the main power source line  41 - 2  is detected. In other words, the sub-power source line  41 - 3  is used as a power supply path for backup. In a case where a load having relatively large power consumption is connected, power is supplied to the same load from both of the main power source line  41 - 2  and the sub-power source line  41 - 3 . This makes it possible to compensate for the shortage of power capacity on the power source side. 
     (3) Switching function between power source types (+B, +BA, IG, and the like): The microcomputer automatically switches between the types of power which is supplied to the power source output portion  41 - 7  from the backup power source circuit  41 - 1 . The types of power include “+B”, “ACC”, “IG”, “+BA”, “IGP”, “IGR”, and the like. 
     “+B” indicates power of a system to which power is normally supplied from a battery. “ACC” indicates power of a system to which power is supplied in conjunction with turning-on and turning-off of an accessory (ACC) switch of a vehicle. “IG” indicates power of a system to which power is supplied in conjunction with turning-on and turning-off of an ignition (IG) switch of a vehicle. “+BA” indicates power of a system which is turned on when a user comes close to a vehicle, and to which power is supplied. “IGP” indicates power of a system which is turned on when ignition switch is brought into an ON state, and then an engine is in a full state, and to which power is supplied. “IGR” indicates a system which indicates a system supplying necessary power during emergency, and to which power is supplied when wheels rotate. 
     The microcomputer performs a process so as to control turning-on and turning-off of each of the two switching elements  41 - 5  depending on situations, and thus the various types of power can be supplied to a load side. 
     &lt;Technique Regarding Power Source Circuit for Power Load&gt; 
       FIG. 42  is an electrical circuit diagram illustrating a configuration example of a power source circuit for power load. 
     A power source circuit  42 - 1  for power load illustrated in  FIG. 42  is provided in each control box CB, and may be used to supply power to, for example, a load requiring particularly large source power. As illustrated in  FIG. 42 , the circuit is provided with a main power source line  42 - 2 , a switching element  42 - 5 , a power source output portion  42 - 6 , and an earth line  42 - 3 . The power source output portion  42 - 6  is connected to a connector  42 - 7  of the control box CB provided for connection of a predetermined branch line sub-harness. 
     The connector  42 - 7  is provided with two terminals  42 - 7   a  and  42 - 7   b . The terminals  42 - 7   a  and  42 - 7   b  are respectively connected to an earth (GND) line and a power source line of the power source output portion  42 - 6 . The respective sizes of the terminals  42 - 7   a  and  42 - 7   b  are all assumed to be 4.8. For example, a blower motor of the vehicle is connected to the connector  42 - 7  via a predetermined power cable. 
     DC power from a main battery or the like of the vehicle is supplied to the main power source line  42 - 2  of the power source circuit  42 - 1  for power load via a backbone trunk line. The earth line  42 - 3  is connected to an earth line of the backbone trunk line or a body ground of the vehicle. 
     A control signal  42 - 4  for controlling turning-on and turning-off of the switching element  42 - 5  is supplied from a microcomputer (not illustrated) provided in the control box CB. The microcomputer appropriately controls the control signal  42 - 4 , and can thus realize the above-described “electronic fuse function”. A timing for supplying power to a load can be appropriately controlled. For example, a control timing may be determined by reflecting a power residual capacity of the main battery, or timing control for power saving may be performed. 
     &lt;Technique for Coping with a Plurality of Communication Protocols&gt; 
       FIG. 44  is a block diagram illustrating a configuration example of a control box which can switch between a plurality of communication protocols. 
     In a communication system on a vehicle, for example, a plurality of kinds of communication interfaces suitable for a standard such as Controller Area Network (CAN) or Clock Extensible 
     Peripheral Interface (CXPI) may be used. If a standard employed by a communication interface of a communication partner differs, a communication specification or a communication protocol differs, and thus communication cannot be performed between each other. Therefore, a communication system is required to be configured so that communication interfaces based on the same standard are connected to each other. 
     Thus, not only the communication interface but also different components are required to be prepared for respective communication standards with respect to a connector or a connection cable, and this leads to an increase in the number of components or an increase in manufacturing cost. 
     Therefore, control boxes  44 - 1  and  44 - 2  illustrated in  FIG. 44  enable common use of a component and automatic switching between protocols in order to cope with protocols based on standards of both of CAN and CXPI. 
     The control box  44 - 1  illustrated in  FIG. 44  has functions of four PHY circuits, two network switches (Switch), and a gateway (GW), controlled by a microcomputer. The gateway copes with communication protocols based on both of the CAN-FD standard and the CXPI standard. 
     A communication interface based on the CAN-FD standard and a communication interface based on the CXPI standard are built in the control box  44 - 1 , and four independent connectors are provided in a connection portion  44 - 1   a  of the control box  44 - 1 . One control box  44 - 1  further includes a wireless PHY circuit. 
     Each connector of the connection portion  44 - 1   a  has a switching circuit  44 - 4  built therein. A CAN connection portion  44 - 4   a  of the switching circuit  44 - 4  is connected to the communication interface based on the CAN-FD standard, and can handle a set of communication signals of “+side” and “−side” based on the CAN-FD standard. A CXPI connection portion  44 - 4   b  of the switching circuit  44 - 4  is connected to the communication interface based on the CXPI standard, and can handle a single communication signal based on the CXPI standard. Signal paths of the CAN connection portion  44 - 4   a  and the CXPI connection portion  44 - 4   b  of the switching circuit  44 - 4  are connected to two terminals of a common connection portion  44 - 4   c  via internal controllable switches. The switches are controlled by the internal gateway (GW). 
     Each of the control boxes  44 - 1  and  44 - 2  is provided with a common connector including four terminals including the two terminals of the common connection portion  44 - 4   c , a power source line and an earth line. 
     A modular cable  44 - 5  illustrated in  FIG. 44  includes four terminals for “GND”, “CAN FD-”, “CAN FD+”, and “power source”, and four electric wires in order to cope with a signal based on the CAN standard. A modular cable  44 - 6  includes four terminals for “GND”, “CXPI”, “GND”, and “power source”, and four electric wires in order to cope with a signal based on the CXPI standard. In other words, the two modular cables  44 - 5  and  44 - 6  have the same number of terminals and the same number of electric wires, and can thus be used as a common component. 
     The modular cable  44 - 5  or the modular cable  44 - 6  having the common configuration is connected to the common connector of the control box  44 - 1 , and can thus cope with any communication based on the CAN-FD standard and the CXPI standard. 
     Actually, under the control of a microcomputer in the control box  44 - 1 , communication based on the CAN-FD standard is selected in an initial state, and automatic switching to communication based on the CXPI standard occurs in a case where a communication apparatus based on the CXPI standard is connected to a partner side. Specifically, when the communication apparatus of the partner side is connected via the modular cable  44 - 5  or  44 - 6 , the microcomputer performs signal scanning so as to recognize a request from the partner. In a case where communication cannot be established by using a protocol based on the CAN standard, communication is tried to be established through switching to a protocol based on the CXPI standard. At this time, the microcomputer changes a switch of the switching circuit  44 - 4  so as to switch signal paths in the switching circuit  44 - 4 , and can thus change a form of a signal flowing through each terminal of the connector to the CXPI form (single signal line) from the CAN form (two signal lines). 
     &lt;Technique Regarding Arrangement of Control Box and ECU&gt; 
       FIG. 43  is a block diagram illustrating a configuration example of an on-vehicle system. 
     In the on-vehicle system illustrated in  FIG. 43 , two control boxes  43 - 1  and  43 - 2  are connected to each other via a backbone trunk line  43 - 4 . An ECU box  43 - 3  is connected to the control box  43 - 1  via a backbone trunk line  43 - 5 . 
     An electronic control unit (ECU) for controlling an air conditioner and a plurality of other ECUs are built in the ECU box  43 - 3 . The control box  43 - 1  is provided in, for example, an instrument panel portion of a vehicle. 
     An ECU  43 - 6  and a connector  43 - 7  are connected to and under the control of the control box  43 - 2  via two modular cables  43 - 8  which are branch lines. A PTC heater  43 - 9  is also connected to and under the control of the control box  43 - 2  via another branch line. A plurality of loads  43 - 10  are connected to output terminals of the ECU  43 - 6 . The connector  43 - 7  has an electronic circuit built therein, and has a function of communicating with the control box  43 - 2  and a function of controlling conduction of a load. 
     In the on-vehicle system illustrated in  FIG. 43 , in a case where an air conditioner as the load  43 - 10  is connected to and under the control of the control box  43 - 2 , a microcomputer in the control box  43 - 2  may perform control of the air conditioner instead of an ECU for controlling the air conditioner in the ECU box  43 - 3 . In this case, the ECU for controlling the air conditioner in the ECU box  43 - 3  may be omitted. 
     On the other hand, in the on-vehicle system illustrated in  FIG. 35 , the control box  35 - 2 A is connected to the ECU box  35 - 3  via the communication line  35 - 6  based on the Ethernet (registered trademark) standard. For example, ten ECUs which are independent from each other can be built in the ECU box  35 - 3 . Therefore, a plurality of ECUs can be disposed at a single location in a concentration manner. Various loads may be connected to and under the control of each ECU in the ECU box  35 - 3 . 
     The ECU box  35 - 3  is provided with a communication interface based on the CAN-FD standard, a gateway (GW), and a PHY circuit. Therefore, each ECU in the ECU box  35 - 3  can communicate with various apparatuses on the vehicle via the control boxes  35 - 2 A to  35 - 2 E. Each ECU built in the ECU box  35 - 3  is attachable and detachable, and may be replaced as necessary. It is also possible to change the mounting position of each ECU. 
     &lt;Technique Regarding Duplication of Communication System&gt; 
       FIGS. 46A and 46B  are block diagrams illustrating a configuration example of an on-vehicle system. 
     In a case where a failure occurs, or a communication line is disconnected due to vehicle crash, communication cannot be performed between apparatuses. However, for example, in a case where a technique such as automatic driving is installed in a vehicle, high reliability is required in a communication system, and thus consideration is required for a communication path not to be disconnected. 
     Therefore, in the on-vehicle system illustrated in  FIGS. 46A and 46B , a power supply path and a communication path are configured to be duplicated for at least a location having high importance in order to increase reliability. 
     In a configuration illustrated in  FIG. 46A , a control box  46 - 1  and a control box  46 - 2  are connected to each other via a backbone trunk line  46 - 4 , and the control box  46 - 1  and a control box  46 - 3  are connected to each other via a backbone trunk line  46 - 5 . Although not illustrated in  FIG. 46 , each of the backbone trunk lines  46 - 4  and  46 - 5  includes a power source line, an earth line, and a communication line, and each of the power source line and the communication line has line paths of two systems which are independent from each other. 
     A control unit  46 - 6  is connected to and under the control of the control box  46 - 2  via a module cable  46 - 7  which is a branch line. A control unit  46 - 6  is connected to and under the control of the control box  46 - 3  via a module cable  46 - 8  which is a branch line. A plurality of loads  46 - 9  are connected to and under the control of the control unit  46 - 6  via a branch line sub-harness  46 - 10 . 
     Each of the module cables  46 - 7  and  46 - 8  includes power source lines of two systems, an earth line, and communication lines of two systems. The earth line may be formed of two systems. 
     For example, a communication path and a power supply path in a case where an instruction is given to the control unit  46 - 6  from the control box  46 - 1  via the backbone trunk line  46 - 4 , the control box  46 - 2 , and the module cable  46 - 7  are duplicated. A communication path and a power supply path in a case where an instruction is given to the control unit  46 - 6  from the control box  46 - 1  via the backbone trunk line  46 - 5 , the control box  46 - 3 , and the module cable  46 - 8  are duplicated. 
     Thus, for example, even in a case where a communication line of one system in one of the backbone trunk lines  46 - 4  and  46 - 5  or one of the module cables  46 - 7  and  46 - 8  is disconnected, a communication path can be secured by using a communication line of the other system which is not disconnected. 
     For example, even in a case where communication lines of two systems in the backbone trunk line  46 - 4  or the module cable  46 - 7  are simultaneously disconnected, switching to the communication path passing through the backbone trunk line  46 - 5 , the control box  46 - 3 , and the module cable  46 - 8  from the control box  46 - 1  occurs, and thus a communication path required to control the control unit  46 - 6  can be secured. 
     On the other hand, in the on-vehicle system illustrated in  FIG. 46B , a central control box  46 - 12  is connected to a plurality of control boxes  46 - 11 ,  46 - 13 ,  46 - 14  and  46 - 15  via independent backbone trunk lines  46 - 17 ,  46 - 16  and  46 - 18 . A control unit or a load is connected to and under the control of each control box via a branch line. 
     For example, a control unit  46 - 21 A is connected to the central control box  46 - 12  via the branch line  46 - 22 , and the control unit  46 - 21 A is connected to the control box  46 - 14  via a branch line  46 - 23 . 
     Therefore, in a case where the control box  46 - 12  gives an instruction to the control unit  46 - 21 A, either one of a communication path passing through the branch line  46 - 22  and a communication path passing through the backbone trunk line  46 - 18 , the control box  46 - 14 , and the branch line  46 - 23  may be used. In other words, even if one of the plurality of paths is disconnected, a necessary communication path can be secured by using remaining normal communication lines. 
     &lt;Technique Regarding Connection Form of Modularized Apparatus&gt; 
       FIG. 47  is a block diagram illustrating a configuration example of a circuit module provided in a driver seat door panel. 
     A circuit module  47 - 4  illustrated in  FIG. 47  is disposed in a driver seat door panel, and is connected to a control box  47 - 1  provided on a vehicle body side via branch line sub-harnesses  47 - 2  and  47 - 3 . The branch line sub-harnesses  47 - 2  and  47 - 3  are routed so as to penetrate through a partition wall at a location where the vehicle body is connected to the driver seat door. 
     A communication line of the branch line sub-harness  47 - 2  is connected to a standard communication interface (CXPI or the like), and a communication line of the branch line sub-harness  47 - 3  is connected to a communication interface based on Ethernet (registered trademark). 
     The circuit module  47 - 4  is provided with not only a modular connection connector  47 - 8  but also a plurality of electronic control units (ECUs)  47 - 10  and  47 - 11  and a side television  47 - 9  as accessories having standard interfaces. An antenna  47 - 5 , a speaker  47 - 6 , a sensor  47 - 7 , a versatile communication connector  47 - 12 , and the like are also provided. 
     The modular connection connector  47 - 8  has three standard communication interfaces based on the CXPI standard and a standard (STD) drive circuit built therein. Each standard communication interface in the modular connection connector  47 - 8  has a function of allowing a received signal to just pass therethrough and sending the signal to an output side. 
     The electronic control units  47 - 10  and  47 - 11  and the versatile communication connector  47 - 12  are respectively connected to the standard communication interfaces of the modular connection connector  47 - 8 . The versatile communication connector  47 - 12  has an electronic circuit built therein, and can perform communication, control on a load, and inputting of a signal by using the electronic circuit. Output terminals of the standard drive circuit of the modular connection connector  47 - 8  are connected to a door lock motor  47 - 17 , and various illumination apparatuses  47 - 18  in the door. 
     The electronic control unit  47 - 10  includes a microcomputer performing a process required to control a power window, and an output terminal thereof is connected to an electric motor (P/W MTR) of the power window. 
     The electronic control unit  47 - 11  includes a microcomputer having a function of controlling an outer mirror provided in the door. Output terminals of the electronic control unit  47 - 11  are connected to constituent elements  47 - 14  and  47 - 15  of the mirror. Output terminals of the versatile communication connector  47 - 12  are connected to a mirror heater  47 - 16 , and a memory switch  47 - 19  and the like. 
       FIG. 48  is a block diagram illustrating a configuration example of a circuit module provided in a passenger seat door panel. 
     A circuit module  48 - 4  illustrated in  FIG. 48  is disposed in a passenger seat door panel, and is connected to a control box  48 - 1  provided on a vehicle body side via branch line sub-harnesses  48 - 2  and  48 - 3 . The branch line sub-harnesses  48 - 2  and  48 - 3  are routed so as to penetrate through a partition wall at a location where the vehicle body is connected to the passenger seat door. 
     A communication line of the branch line sub-harness  48 - 2  is connected to a standard communication interface (CXPI or the like), and a communication line of the branch line sub-harness  48 - 3  is connected to a communication interface based on Ethernet (registered trademark). 
     The circuit module  48 - 4  is provided with not only a modular connection connector  48 - 8  but also a plurality of electronic control units (ECUs)  48 - 10  and  48 - 11  and a side television  48 - 9  as accessories having standard interfaces. An antenna  48 - 5 , a speaker  48 - 6 , a sensor  48 - 7 , a versatile communication connector  48 - 12 , and the like are also provided. 
     The modular connection connector  48 - 8  has three standard communication interfaces based on the CXPI standard and a standard (STD) drive circuit built therein. The electronic control units  48 - 10  and  48 - 11  and the versatile communication connector  48 - 12  are respectively connected to the standard communication interfaces of the modular connection connector  48 - 8 . The versatile communication connector  48 - 12  has an electronic circuit built therein, and can perform communication, control on a load, and inputting of a signal by using the electronic circuit. Output terminals of the standard drive circuit of the modular connection connector  48 - 8  are connected to a door lock motor  48 - 17 , and various illumination apparatuses  48 - 18  in the door. 
     The electronic control unit  48 - 10  includes a microcomputer performing a process required to control a power window, and an output terminal thereof is connected to an electric motor (P/W MTR) of the power window. 
     The electronic control unit  48 - 11  includes a microcomputer having a function of controlling an outer mirror provided in the door. Output terminals of the electronic control unit  48 - 11  are connected to constituent elements  48 - 14  and  48 - 15  of the mirror. Output terminals of the versatile communication connector  48 - 12  are connected to a mirror heater  48 - 16 , and a lamp  48 - 19 . 
       FIG. 49  is a block diagram illustrating a configuration example of a circuit module provided in a rear seat door panel. The left and right rear seat door panels have the same configuration. 
     A circuit module  49 - 3  illustrated in  FIG. 49  is disposed in a rear seat door panel (each of the left and right door panels), and is connected to a control box  49 - 1  provided on a vehicle body side via a branch line sub-harness  49 - 2 . The branch line sub-harness  49 - 2  is routed so as to penetrate through a partition wall at a location where the vehicle body is connected to the rear seat door. A communication line of the branch line sub-harness  49 - 2  is connected to a standard communication interface (CXPI or the like). 
     The circuit module  49 - 3  is provided with not only a modular connection connector  49 - 4  but also an electronic control unit (ECU)  49 - 5  and the like as accessories having standard interfaces. The modular connection connector  49 - 4  has three standard communication interfaces based on the CXPI standard and a standard (STD) drive circuit built therein. The electronic control unit  49 - 5  is connected to the standard communication interfaces of the modular connection connector  49 - 4 . 
     Output terminals of the standard drive circuit of the modular connection connector  49 - 4  are connected to a door lock motor  49 - 7 , and various illumination apparatuses  49 - 8 ,  49 - 9  and  49 - 10  in the door. 
     The electronic control unit  49 - 5  includes a microcomputer performing a process required to control a power window, and an output terminal thereof is connected to an electric motor (P/W MTR)  49 - 6  of the power window. 
       FIG. 50  is a block diagram illustrating a configuration example of a circuit module provided in a vehicle&#39;s roof. 
     A circuit module  50 - 3  illustrated in  FIG. 50  is disposed in a roof portion of a vehicle body, and is connected to a control box  50 - 1  provided on a vehicle interior side via a branch line sub-harness  50 - 2 . The branch line sub-harness  50 - 2  is routed so as to penetrate through a partition wall at a location where the vehicle body is connected to the roof. A communication line of the branch line sub-harness  50 - 2  is connected to a standard communication interface (CXPI or the like). 
     The circuit module  50 - 3  is provided with not only a modular connection connector  50 - 4  but also an electronic control unit (ECU)  50 - 6 , a rain sensor  50 - 14  and the like as accessories having standard interfaces. A microphone  50 - 5 , a versatile communication connector  50 - 7 , and the like are also provided. 
     The modular connection connector  50 - 4  has three standard communication interfaces based on the CXPI standard and a standard (STD) drive circuit built therein. Each standard communication interface in the modular connection connector  50 - 4  has a function of allowing a received signal to just pass therethrough and sending the signal to an output side. 
     The electronic control unit  50 - 6 , the rain sensor  50 - 14 , and the versatile communication connector  50 - 7  are respectively connected to the standard communication interfaces of the modular connection connector  50 - 4 . The versatile communication connector  50 - 7  has an electronic circuit built therein, and can perform communication, control on a load, and inputting of a signal by using the electronic circuit. Output terminals of the standard drive circuit of the modular connection connector  50 - 4  are connected to various lamp loads  50 - 12  and  50 - 13 . 
     The electronic control unit  50 - 6  includes a microcomputer performing a process required for drive control such as closing and opening of a sliding roof, and output terminals thereof are connected to a sliding roof switch  50 - 8  and a drive electric motor  50 - 9 . Output terminals of the versatile communication connector  50 - 7  are connected to a Mayday switch  50 - 10  and an inner rearview mirror  50 - 11 . 
       FIG. 51  is a block diagram illustrating a configuration example of a smart connection connector. A smart connection connector  51 - 3  illustrated in  FIG. 51  is an element providing a joint function which can be used at various locations on a vehicle in a versatile manner, and may be connected to a desired control box via a branch line sub-harness  51 - 2  and a standard interface  51 - 1 . 
     As illustrated in  FIG. 51 , an output side connector  51 - 7  of the smart connection connector  51 - 3  may be connected to a door lock motor switch  51 - 8 , various illumination apparatuses  51 - 9 ,  51 - 10  and  51 - 11 , a door lock motor  51 - 12 , and the like. 
     A control circuit  51 - 4  is provided in the smart connection connector  51 - 3 . The control circuit  51 - 4  includes a standard communication interface  51 - 4   a , a power source circuit  51 - 4   b , a microcomputer (CPU)  51 - 4   c , a signal processing circuit (STRB)  51 - 4   d , an input circuit  51 - 4   e , an intelligent power device (IPD)  51 - 4   f , and a motor driver  51 - 4   g.    
     The output side connector  51 - 7  of the smart connection connector  51 - 3  is provided with terminals for outputting various types of source power, a communication terminal, a terminal for a signal to be input to the input circuit  51 - 4   e , a terminal for connection of a load driven by the IPD  51 - 4   f , and a terminal for connection of an electric motor. 
     Source power output from the output side connector  51 - 7  is used to operate an electronic fuse or to switch between the types of power (+B, +BA, IG, and the like) through processing in the microcomputer  51 - 4   c . In order to perform this control, switching elements are connected between respective terminals of the output side connector  51 - 7  and an input side power source line. Turning-on and turning-off of the switching elements are controlled by the microcomputer  51 - 4   c.    
     &lt;Technique for Adding Function by Adding New Unit&gt; 
     In the present embodiment, control of a system side is assumed in a case where a function is added by connecting a new unit to a common interface of an on-vehicle system. For example, in the system illustrated in  FIG. 2 , a case is assumed in which a new accessory AE is connected to the connector of the connection portion Cnx of each control box CB via the branch line sub-harness LS. However, the newly connected unit cannot be said to be a legal unit, and thus it is necessary to perform special control in order to ensure the security of the entire system. 
     Although not illustrated, specific examples of procedures performed in this case are as follows. 
     Step S 50 : In a dealer or the like of a vehicle, a worker or the like connects a corresponding new unit (accessory) to the connection portion Cnx of the control box CB via the branch line sub-harness LS. 
     Step S 51 : In the dealer or the like of the vehicle, the worker or the like connects a diagnosis tool (for example, “TaSCAN”) dedicated to a vehicle, provided by a vehicle manufacturer or the like to a system on the vehicle, and executes a command for scanning in order to diagnose the connected unit. 
     Step S 52 : The microcomputer of the control box CB starts a scanning process in response to the command from the diagnosis tool. First, power is supplied to a first standard interface which is initially connected to the connection portion Cnx, and the microcomputer automatically identifies whether or not the CAN standard communication can be performed with respect to communication using the standard interface. 
     Step S 53 : In a case where the CAN standard communication is not established in step S 52 , the microcomputer switches a communication specification to CXPI from CAN, and identifies whether or not the CXPI standard communication can be performed. 
     Step S 54 : In a case where neither of the CAN standard communication and the CXPI standard communication is established in steps S 52  and S 53 , the microcomputer stops the supply of power to the standard interface. 
     Step S 55 : In a case where the CAN or CXPI standard communication is established in steps S 52  and S 53 , communication is performed among the diagnosis tool, the microcomputer of the control box CB, and the accessory (the new unit or the like) which is a connection destination, and the diagnosis tool performs a predetermined process so as to perform an authentication process on the accessory. The content of the authentication process is standardized in advance. 
     Step S 56 : In a case where the authentication is successful in step S 55 , the microcomputer of the control box CB registers conditions of supplying source power to the accessory based on the standard interface in a storage device of the microcomputer. For example, it is automatically identified that the kind of power to be supplied is any one of “+B, +BA, IG, and IGP” on the basis of the kind of the accessory proved through the authentication, or ID information, and the identification result is registered. 
     Step S 57 : The processes in steps S 52  to S 56  are sequentially performed on second and subsequent standard interfaces repeatedly. 
     Step S 58 : After the scanning process on all of the standard interfaces is completed, the diagnosis tool or the microcomputer of the control box CB displays a message or the like so that a user (or a worker) can confirm addition of a function with respect to the added new unit. This display is performed by using, for example, a display portion of the meter unit on the vehicle. 
     Step S 59 : The microcomputer of the control box CB stores, in the storage device thereof, information for transfer to the function confirmed by the user in step S 58  to an environment in which the function can be actually used. 
     Therefore, for example, even if an illegal apparatus which is not allowed by a vehicle manufacturer or the like is tried to be connected to the on-vehicle system by a user or a third party, the illegal apparatus cannot perform communication with the legal on-vehicle system, and cannot be supplied with power via a communication connector either, and thus the illegal apparatus cannot operate at all. 
     &lt;Technique Regarding Connection Form of Communication System in On-Vehicle System&gt; 
       FIG. 52A ,  FIG. 52B  and  FIG. 53  are block diagrams respectively illustrating configuration examples of communication systems in different on-vehicle systems. 
     An on-vehicle system illustrated in  FIG. 52A  includes communication networks V 2 -CAN, V 1 -CAN, and MS-CAN of three systems, which are connected to each other via a gateway. The communication network V 2 -CAN is allocated to apparatuses of an engine compartment (engine room), the communication network V 1 -CAN is allocated to apparatuses (including a meter unit) of an engine system, and the communication network MS-CAN is allocated to apparatuses (doors, power seats, and the like) of a body system. 
     The communication network MS-CAN is disposed in the entire vehicle as a domain, and each of the communication networks V 1 -CAN and V 2 -CAN is divided for area on a vehicle body. Various accessories are connected to and under the control of each of the communication networks MS-CAN, V 1 -CAN and V 2 -CAN. 
     In an on-vehicle system illustrated in  FIG. 52B , a plurality of communication networks respectively in charge of a plurality of domains which are respectively allocated to a driving assistance system, a power train system, a chassis system, a body system, and a multimedia system are connected to each other. Each communication network employs a communication interface based on the CAN standard. These sets of communication networks are routed to extend in parallel to each other in the entire region of the vehicle. 
     In an on-vehicle system illustrated in  FIG. 53 , a domain is divided for each area such as an “area  1 ”, an “area  2 ”, an “area  3 ”, an “area  4 ”, and an “area  5 ”, and a communication network is formed in each area. An optical communication network is used for a trunk line connecting the respective areas to each other in order to enable high-speed communication. 
     By using the optical communication network, high-speed communication of, for example, about 1 Gbps can be performed between the areas. A communication capacity of the optical communication network is distributed to a plurality of systems in the communication network of each area, so as to be allocated to communication of various accessories. The priority of communication is determined on the basis of specific ID information allocated to each of apparatuses such as accessories in advance. 
     &lt;Technique Regarding Internal Configuration of Control Box&gt; 
       FIG. 45  is a block diagram illustrating a configuration example of a control box. 
     An on-vehicle system illustrated in  FIG. 45  includes five control boxes  45 - 1 ,  45 - 2 ,  45 - 3 ,  45 - 4  and  45 - 5  connected to each other via backbone trunk lines  45 - 7  and  45 - 8 , and an ECU box  45 - 6 . 
     As illustrated in  FIG. 45 , the backbone trunk line  45 - 7  includes power source lines of two systems and an earth line. The backbone trunk line  45 - 8  includes communication lines of two systems. 
     The control box  45 - 1  is provided with power source portions  45 - 10  of two systems, two sets of network (Ethernet: registered trademark) hubs  45 - 11  and  45 - 12 , a communication control unit  45 - 13  of a gateway (GW), a WiFi communication module  45 - 14 , a network (Ethernet: registered trademark) hub  45 - 15 , a power control unit  45 - 16 , switching circuits  45 - 17 A,  45 - 17 B and  45 - 17 C, and connectors  45 - 21 ,  45 - 22 ,  45 - 23  and  45 - 24 . 
     Of the communication lines of two systems included in the backbone trunk line  45 - 8 , one communication line is connected to the network hub  45 - 11 , and the other communication line is connected to the network hub  45 - 12 . The communication system of the network hub  45 - 11  side is allocated for use in a power train system and a chassis system of a vehicle, and the communication system of the network hub  45 - 12  side is allocated for use in a body system and a multimedia system of the vehicle. 
     The communication control unit  45 - 13  of the gateway (GW) is a functional unit realized under the control of a microcomputer (not illustrated) provided in the control box  45 - 1 , and has the following functions. 
     (1) Interconnection between a plurality of networks based on different standards such as protocols 
     (2) Reception of related packet 
     (3) Transmission of signal 
     (4) Classification of communication of a control system and communication of a driving assistance system 
     (5) Bypass communication of high-rank information 
     The WiFi communication module  45 - 14  is used for wirelessly connecting the control box  45 - 1  to other apparatuses mounted on the vehicle or an apparatus carried by a user. 
     The network hub  45 - 15  has a function of dividing one communication path from the communication control unit  45 - 13  for connection to any one of communication paths of the connectors  45 - 21 ,  45 - 22  and  45 - 23 . 
     The power control unit  45 - 16  is a functional portion realized under the control of the microcomputer (not illustrated) provided in the control box  45 - 1 , and has source power control functions as described below. 
     (1) Electronic fuse function of blocking path when overcurrent flows; 
     (2) Function of controlling the kinds of power such as “+B, +BA, IGP, and IGR”; 
     (3) Function of backing up power source of an important system by properly using power source lines of two systems when abnormality occurs in power source; and 
     (4) Stop &amp; start (S &amp; S) switching function. 
     Each of the switching circuits  45 - 17 A,  45 - 17 B and  45 - 17 C includes two controllable switching elements for respectively connecting the power source lines of two systems to power source lines of the connectors  45 - 21 ,  45 - 22  and  45 - 23 . The switching elements are separately controlled to be turned on and off according to control signals output from the microcomputer which realizes each function of the power control unit  45 - 16 . 
     Each of the connectors  45 - 21 ,  45 - 22  and  45 - 23  includes four terminals such as a power source line terminal, an earth line terminal, and two communication line terminals Various kinds of accessories can be connected to and under the control of the connectors  45 - 21 ,  45 - 22  and  45 - 23  via predetermined branch line sub-harnesses. 
     As mentioned above, according to the vehicular circuit body of the present invention, it is possible to easily add a new electric wire by simplifying a structure for electrical connection between various electric components and a power source on a vehicle and between the electric components, particularly, a configuration of a trunk line portion. 
     Aspects of the vehicular circuit body in accordance with the embodiments of the invention disclosed in the above are briefly summarized and respectively listed in [1] to [7] as follows: 
     [1] A vehicular circuit body provided in a vehicle includes: 
     a trunk line (backbone trunk line  21 ,  22 ,  23 ) that extends in at least a front-and-rear direction of the vehicle; and 
     a plurality of control boxes (backbone control boxes  31 ,  32 ,  33 ) that are provided in the trunk line. 
     Each of the plurality of control boxes is able to connect with a branch line (branch line sub-harness LS) that is directly or indirectly connected to an accessory, and 
     The trunk line includes a power source line (L 1 , L 2 ) having a predetermined current capacity and a communication line (L 4 , L 5 ) having a predetermined communication capacity. 
     [2] In the vehicular circuit body according to [1], the trunk line includes power source lines (L 1 , L 2 ) of two systems. 
     [3] In the vehicular circuit body according to [1], the branch line includes a power source line and a communication line, each of the plurality of control boxes includes a branch line connection portion (switch circuit CBb, bridge circuit Cbc, connection portion Cnx) to which the branch line is connected, and a branch line control unit (microcomputer Cba) that distributes power from the trunk line to the branch line by controlling the branch line connection portion according to a control program, and the control program can be externally changed according to the accessory connected to the branch line.
 
[4] In the vehicular circuit body according to [1], the communication line (BB_LC) of the trunk line is routed so that the plurality of control boxes are connected in a ring form.
 
[5] In the vehicular circuit body according to [1], the branch line includes a power source line and a communication line,
 
     each of the plurality of control boxes includes a plurality of branch line connection portions (Cnx) to and from which the communication line of the branch line is attachable and detachable, and each of the plurality of branch line connection portions is provided with a lock function portion (a cover member (cover with key Kc 1 ) and key part (Kk), (cover with key Kc 2 ) and key part (Kk), (seal for sealing Ks) or steps S 12 -S 14 ) that is physically or electrically brought into a lock state in a case where the branch line is not connected thereto. 
     [6] In the vehicular circuit body according to [1], the branch line includes a power source line and a communication line, 
     the vehicle is divided into a plurality of regions (AR 1 , AR 2 , AR 3 ), 
     at least two control boxes are disposed in the regions which are different from each other, each of which includes a gateway (GW) conversing communication methods for the communication line of the branch line and the communication line of the trunk line, and 
     a plurality of the gateways are able to communicate with each other via the communication line (BB_LC) of the trunk line. 
     [7] In the vehicular circuit body according to [1], the branch line includes at least one of a power source line and a communication line, 
     the communication line of the trunk line has a transmission path for an optical signal (optical fiber), and 
     the communication line of the branch line has a transmission path for an electric signal (metal communication line). 
     While the present invention is described in detail by referring to the specific embodiments, it is to be understood to a person with ordinary skill in the art that various changes or modifications may be made without deviating from the spirit and scope of the present invention. 
     The present application is based on Japanese Patent Application No. 2016-125287 filed on Jun. 24, 2016, Japanese Patent Application No. 2016-125896 filed on Jun. 24, 2016, and Japanese Patent Application No. 2016-131165 filed on Jun. 30, 2016, the contents of which are incorporated herein by reference. 
     According to the invention, effects is that, in a vehicular circuit body, structures for electric connections between various electric components and power sources on a vehicle and between the electric components, specifically configurations on trunk line portions are simplified, and additional cables are easy to be added. The invention having the effects is useful on the vehicular circuit body routed in the vehicle. 
     REFERENCE SIGNS LIST 
     
         
         
           
               21 ,  22 , AND  23  BACKBONE TRUNK LINE PORTION 
               31 ,  32 , AND  33  BACKBONE CONTROL BOX 
             AE ACCESSORY 
             ALT ALTERNATOR 
             MB MAIN BATTERY 
             BB_LM BACKBONE TRUNK LINE 
             CB CONTROL BOX 
             LS BRANCH LINE SUB-HARNESS 
             Cnx CONNECTION PORTION 
             L 1 , L 2 , AND L 2 B POWER SOURCE LINE 
             L 3  EARTH LINE 
             L 4 , L 5 , AND Lx COMMUNICATION LINE 
             DT DIAGNOSIS TOOL 
             CBa MICROCOMPUTER 
             CBb SWITCH CIRCUIT 
             CBc BRIDGE CIRCUIT 
             BB_LC COMMUNICATION TRUNK LINE 
             AR 1 , AR 2 , AND AR 3  AREA 
             CBd CIRCUIT BOARD 
             Kc 1  AND Kc 2  COVER WITH KEY 
             Kk UNLOCK KEY 
             Ks SEAL FOR SEALING 
             GW GATEWAY 
             CB 01  POWER SOURCE CIRCUIT 
             CB 02  GATEWAY CONTROL CIRCUIT 
             CB 03 , CB 04 , CB 05 , AND CB 06  PHY CIRCUIT 
             CB 07  AND CB 08  NETWORK SWITCH 
             CB 09  AND CB 10  TRANSCEIVER 
             CB 11  SWITCHING CIRCUIT 
             CP 1  TO CP 8  COMMUNICATION PORT CONNECTOR 
             LPP 1  AND LPP 2  COMMUNICATION LINE 
             FBC 1  AND FBC 2  OPTICAL FIBER CABLE 
             FB 11  AND FB 12  OPTICAL FIBER