Patent Publication Number: US-2009219948-A1

Title: Connection adapter for communication device

Description:
TECHNICAL FIELD 
     The present invention relates to the field of telemetring for collecting sales information about a vending machine and the field of telematics for distributing traffic information to a mobile object. 
     BACKGROUND ART 
     Recently, telemetring and telematics for collecting and distributing information over a wireless packet communication network have become widespread. The telemetring originally refers to a system of reading a measured value by a measure via a communication line. However, it has been generally used as a term indicating not only reading data but also monitoring the operation of equipment and performing remote control. A typical example of telemetring is a sales management system of a vending machine, a use amount management system of a gas, water supply, etc., a management system in a parking lot without humans in attendance, etc. For a sales management system of a vending machine, refer to the patent document 1. The telematics refers to providing information in real time by combining a mobile object such as an automobile with a communication system. A typical example of telematics can be a vehicle-mounted information system etc. for providing in real time a terminal provided for a vehicle with traffic information and navigation information. 
     In the fields above, communication equipment for connection to a wireless packet communication network in a remote location and a host device to the communication equipment are arranged. The host device corresponds to data terminal equipment (DTE). The communication equipment corresponds to data circuit-terminating equipment (DCE). 
     For example, in the sales management system of a vending machine, the control device for controlling the sales and the temperature in the machine correspond to the host device. Each host device is periodically or arbitrarily connected to a predetermined network through communication equipment, and to a predetermined managing computer over the network. The host device connected to the managing computer transmits various types of data to be managed. 
     Patent Document 1: Japanese Patent Publication 2003-51056 
     DISCLOSURE OF THE INVENTION 
     Problems to be Solved by the Invention 
     In the conventional system, there can be a request to change the communication partner of a host device into another managing computer as necessary. For example, there can be a request to exchange a managing computer or change a network to which the managing computer belongs. In this case, an IP address etc. of the managing computer is changed. However, the IP address etc. of a host device is often set fixedly for connection only to a specific managing computer. Therefore, the request cannot be satisfied. 
     In addition, there can be a request to allow a host device to communicate with a plurality of managing computers. For example, communications of data to be managed are performed with a first managing computer, and communications is performed with a second managing computer for the update of firmware, the monitor of a state, etc. However, since the IP address etc. of a host device is often set fixedly for connection only to a specific managing computer as described above, the above-mentioned request cannot be satisfied. 
     The present invention has been developed to solve the above-mentioned problems, and aims at providing a connection adapter for communication device capable of communicating with any computer. 
     Means for Solving the Problems 
     To attain the above-mentioned advantages, the present invention proposes a connection adapter for communication device including: a first interface for connecting communication equipment for a network connection service; a second interface for connecting a host device for performing communication using the communication equipment; a connection control unit for performing a network connecting process; a communication control unit for relaying communications using the communication equipment by the host device; and storage means for storing a telephone number associated with connection destination information required for network connection. With the configuration, upon receipt of a connection request including a telephone number from the host device, the connection control unit acquires the connection destination information from the storage means on a basis of the telephone number, and performs a network connecting process according to the connection destination information. 
     According to the present invention, upon receipt of a connection request including a telephone number from a host device, the connection adapter performs connection to a network according to the connection destination information associated with the telephone number. Therefore, by appropriately changing the connection destination information stored in the storage means of the connection adapter, thereby easily changing a connection destination of the host device. 
     The host device corresponds to data terminal equipment (DTE). The communication equipment corresponds to data circuit-terminating equipment (DCE). 
     In the present application, in the above-mentioned connection adapter, the communication equipment is used for a network connection service of assigning a dynamic IP address to a connection terminal, and the connection control unit of the connection adapter acquires the connection destination information from the storage means at a connection start request when the communication equipment receives the connection start request from a network side, and the network connecting process is performed using the connection destination information. 
     According to the present invention, the connection destination information is acquired at a connection request received from the network side regardless of the telephone number included in the connection request issued by the host device, and a connection is made to a network according to the connection destination information. Therefore, communications can be performed with a computer other than a connection destination corresponding to the telephone number issued from the host device. An example of a connection start request from the network side can be a request received from a messaging service provided by a network connection service. 
     “Dynamically assigning an IP address” means issuing an IP address from a communication network to a wireless communication terminal when the wireless communication terminal is connected to a wireless packet communication network. Issuing an IP address can be performed by assigning one of the IP addresses included in a predetermined range, or by fixedly assigning an IP address corresponding to a wireless communication terminal, which depends on the service mode in the wireless packet communication network. 
     In the present application, in the connection adapter, the communication control unit converts an IP address stored in the header of the IP packet. 
     According to the present invention, the host device can be connected to a network or a computer having an IP address different from the predetermined IP address. 
     ADVANTAGES OF THE INVENTION 
     As described above, according to the present invention, the connection adapter performs connection to a network according to the connection destination information associated with a telephone number when a connection request including a telephone number is received from the host device. Therefore, the connection destination of the host device can be easily changed by appropriately changing the connection destination information stored in the storage means of the connection adapter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows the configuration of a communication system according to an embodiment of the present invention; 
         FIG. 2  is an explanatory view of an address management table; 
         FIG. 3  shows a network of a communication system according to an embodiment of the present invention; 
         FIG. 4  shows the configuration of a connection adapter; 
         FIG. 5  is a block diagram showing the function of a main control unit of a connection adapter; 
         FIG. 6  is an explanatory view of an example of the setting information in the connection adapter; 
         FIG. 7  is a block diagram showing the function of a network router; 
         FIG. 8  is an explanatory view of an example of a host device information table; 
         FIG. 9  is an explanatory view of an example of the address conversion table; 
         FIG. 10  is an explanatory view of the sequence of offering a network connection service as a presumption and starting communications from the host device; 
         FIG. 11  is an explanatory view of the sequence of offering a network connection service as a presumption and starting communications from a managing computer; 
         FIG. 12  is an explanatory view of the sequence of starting communications from the host device according to the first embodiment of the present invention; 
         FIG. 13  is an explanatory view of the sequence of starting communications from the host device according to the first embodiment of the present invention; 
         FIG. 14  is an explanatory view of an address converting process; 
         FIG. 15  is an explanatory view of the sequence of starting communications from the managing computer according to the first embodiment of the present invention; 
         FIG. 16  is an explanatory view of the sequence of starting communications from the managing computer according to the first embodiment of the present invention; 
         FIG. 17  is an explanatory view of the address converting process; 
         FIG. 18  shows the configuration of the communication system according to the second embodiment of the present invention; 
         FIG. 19  is an explanatory view showing an example of an address management table; 
         FIG. 20  is an explanatory view of the sequence of starting communications from the host device according to the second embodiment of the present invention; 
         FIG. 21  is an explanatory view of the address converting process; 
         FIG. 22  is an explanatory view of the sequence of starting communications from the managing computer according to the second embodiment of the present invention; 
         FIG. 23  is an explanatory view of the sequence of starting communications from the managing computer according to the second embodiment of the present invention; and 
         FIG. 24  is an explanatory view of the address converting process. 
     
    
    
     DESCRIPTION OF SYMBOLS 
     
         
           1  connection adapter 
           120  main control unit 
           121  line control unit 
           122  communication control unit 
           10  host device 
           20 ,  25 ,  26  communication module 
           40 ,  45 ,  45  wireless packet communication network 
           42  messaging server 
           43  address management server 
           50 ,  55  in-house LAN 
           51 ,  56  managing computer 
           60  network router 
           62  line control unit 
           64  communication control unit 
           65  setting data storage unit 
           65   a  host device information table 
           65   b  address conversion table 
       
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     First Embodiment 
     The communication system according to a first embodiment of the present invention is described below with reference to the attached drawings.  FIG. 1  shows the configuration of a telemetring system using the communication system according to the present invention. 
     This system aims at providing a network environment obtained by connecting a host device  10  of, for example, a control device of a vending machine to a first in-house LAN  50  and a second in-house LAN  55  over a wireless packet communication network  40  as shown in  FIG. 1 . It is assumed that the host device  10  and a terminal (in the example shown in  FIG. 1 , a managing computer  51  of a vending machine etc.) in the in-house LANs  50  and  55  is set for a network connection service for assigning a fixed IP address. The main advantage of the present system is to allow the wireless packet communication network  40  to use a network connection service for assigning a dynamic IP address to a connection terminal without reforming a terminal in the host device  10  and the in-house LANs  50  and  55 . The communication system is described below in detail. 
     The host device  10  corresponds to data terminal equipment (DTE). The host device  10  is designed to correspond to a specific carrier and a network connection service provided by the carrier. Practically, it is assumed that the host device  10  uses a network connection service of assigning a fixed IP address to a connection terminal. In addition, the host device  10  is designed to connect a communication module corresponding to the service, and correspond to a connection protocol, an authentication protocol, etc. corresponding to the service. 
     The network connection service upon which the host device  10  is based is described below. In the network connection service, a telephone number is assigned to a communication module in advance by a carrier. In the wireless packet communication network under the network connection service is provided with a relay device for performing line control, packet relay, etc. In the relay device, a telephone number is assigned to an in-house LAN as a connection destination network. Upon issue of a call to the telephone number of the relay device in the wireless packet communication network, a terminal having a connected communication module makes a connection to a predetermined network such as an in-house LAN corresponding to the telephone number. A connection to the relay device is allowed only from a communication module having a telephone number assigned in advance. 
       FIG. 2  shows an example of a network using a network connection service upon which the host device  10  is based. As shown in  FIG. 2 , the host device  10  performs a connection to wireless packet communication network  45  configured by the network connection service using communication module  25 . In the present embodiment, the wireless packet communication network  45  and the communication module  25  are assumed to be in accordance with the PDC standard. Furthermore, in the service, an IP address belonging to the network of 192.168.0.0/28 is fixedly assigned to the WAN side interface of a network router  60  and the communication module  25 . The host device  10  is connected to the LAN  50  in the terminal type network connection service. Therefore, the IP address assigned to the communication modules  25  and  26  is similar to the IP address assigned to the host device  10 . It is assumed that, in the in-house LAN  50 , a fixed IP address of each device is assigned so that it can belong to the network of 192.168.9.0/24. Upon receipt of a packet with an IP address in the 192.168.0.0/28 from the in-house LAN  50 , the network router  60  relays the packet to the wireless packet communication networks  45  and  46 . On the other hand, upon receipt of a packet with an IP address in the 192.168.9.0/24 from the wireless packet communication networks  45  and  46 , the network router  60  relays the packet to the in-house LAN  50 . With the configuration, the managing computer  51  can start communications to a fixed IP address of the host device  10 . In addition, the managing computer  51  can designate the host device  10  with reference to the source IP address of the communication from the host device  10 . The host device  10  is set to be connected only to the first in-house LAN  50 , and is not designed to be connected to the second in-house LAN  55 . 
     The present invention is based on the use of the host device  10  and the managing computer  51 , and it is assumed that a network system can be configured in the wireless packet communication network  40  under the network connection service in which a dynamic IP can be assigned. Furthermore, the present invention enables the communications with the second in-house LAN  55  not presumed by the host device to be performed. 
     Next, a network connection service used in an embodiment of the present invention, and in which a dynamic IP address is assigned is described below. In the network connection service, a telephone number is assigned in advance by a carrier to a communication module  20 . The wireless packet communication network  40  is provided with a relay device  41  for controlling a line and relaying a packet etc. as shown in  FIG. 1 . A terminal to which the communication module  20  is connected is connected to the wireless packet communication network  40  by issuing a call with a predetermined special number assigned. Then, the terminal can be connected to the in-house LANs  50  and  55  as a connection destination network by performing an authenticating process using a PAP (password authentication protocol) with the relay device  41 . In the above-mentioned PAP authentication, a connection destination network can be specified by including the information specifying a connection destination in a user name. To be more concrete, a user is authenticated and a connection destination is designated in the format of a user name @ domain name by describing the connection destination information as a domain name. In the network connection service, an IP address group in a predetermined range is allocated by a carrier to the wireless packet communication network  40 , and an IP address contained in the IP address group is dynamically assigned by the IPCP (Internet protocol control protocol) to the communication module  20 . The IP address to be assigned to the communication module  20  is not fixed, and the same IP address as in the preceding connection, or a different address can be assigned. 
     In the network connection service, it is assumed that a messaging service is provided for a user. The messaging service is not a network connection service using a TCP/IP, but is implemented by a unique protocol using a wireless communication network. In this messaging service, the wireless packet communication network  40  or a predetermined messaging server  42  provided for another network such as the Internet etc. are assigned the telephone number of the communication module  20 , thereby enabling a relatively short message to be transmitted. The HTTP is used in a message transmission request to the messaging server  42 . 
     Next, the chart of the network of the system according to the present embodiment is described below with reference to  FIG. 3 .  FIG. 3  is a chart of the network of the present system. As shown in  FIG. 3 , in this system, a fixed IP address belonging to 192.168.0.0/28 is assigned to the host device  10  and the first in-house LAN  50  as in the network described above with reference to  FIG. 2 . 
     When a connection is made to the first in-house LAN  50 , the wireless packet communication network  40  is assigned an address group of 172.16.0.0/28. The WAN side of the network router (hereinafter referred to simply as a “router”)  60  at the boundary point between the wireless packet communication network  40  and the in-house LAN  50  is assigned a fixed IP address 172.16.0.14. The communication module  20  is assigned a dynamic address in 172.16.0.0/28 when it is connected to the wireless packet communication network  40  (in  FIG. 4 , it is expressed by 172.16.0.X for convenience). A connection adapter  1  is connected to the LAN  50  with the terminal type network connection service. Therefore, the IP address of the connection adapter  1  is an IP address dynamically assigned to the communication module  20 . When the connection adapter  1  is connected to the first in-house LAN  50 , example 1 is specified as a domain name when an authenticating process is performed. 
     On the other hand, when a connection is made to the second in-house LAN  55 , the wireless packet communication network  40  is assigned an address group of 172.16.9.0/28. A fixed IP address 172.16.9.15 is assigned to the WAN side of a network router (hereinafter referred to simply as a router)  65  as a boundary point between the wireless packet communication network  40  and the in-house LAN  55 . In addition, the communication module  20  is dynamically assigned an address in 172.16.9.0/28 when a connection is made to the wireless packet communication network  40  (in  FIG. 3 , it is expressed by 172.16.9.X for convenience). The connection adapter  1  is connected to the LAN  55  in the terminal type network connection service. Therefore, the IP address of the connection adapter  1  is an IP address dynamically assigned to the communication module  20 . When the connection adapter  1  is connected to the second in-house LAN  55 , example 2 is specified as a domain name when an authenticating process is performed. The second in-house LAN  55  is fixedly assigned an IP address to belong to the network of 192.168.99.0/24. 
     In the above-mentioned network environment in the present invention, communications can be started from the first managing computer  51  in the first in-house LAN  50  to the host device  10 , and the host device  10  can be designated when communications are started from the host device  10  to the first managing computer  51 . Furthermore, communications are started from a second managing computer  56  in the second in-house LAN  55  to the host device  10 . 
     Next, the connection adapter  1  is described below. The connection adapter  1  connects plural types of host devices  10  to plural types of communication modules  20 ,  25 , and  26 . In the connection adapter  1  according to an embodiment of the present invention, it corresponds to the communication module  20  in accordance with the CDMA standard, the communication module  25  in accordance with the PDC standard, and the communication module  26  in accordance with the PHS standard. Each of the communication modules  20 ,  25 , and  26  is communication equipment connected to the wireless packet communication network  40 ,  45 , and  46  configured by the respective carriers. Each carrier corresponds to a uniquely determined communication standard and communication protocol service. As described above, the host device  10  is designed to correspond to a specific carrier and a service provided by the carrier. Practically, a communication module corresponding to the service is connected, and the connection protocol and the authentication protocol can be satisfied corresponding to the service. 
     The host device  10  according to an embodiment of the present invention is assumed to be directly connected to the communication module  25  in accordance with the PDC standard, and the communication module  26  in accordance with the PHS standard. Using the communication modules  25  and  26 , it can be connected only to the first in-house LAN  50  over each of the wireless packet communication networks  45  and  46 . The connection adapter  1  according to an embodiment of the present invention can be connected to the in-house LANs  50  and  55  through the wireless packet communication network  40  using the communication module  20  in accordance with the CDMA without improving or changing the host device  10 . The connection adapter  1  is described below in more detail. 
     First, the configuration of the connection adapter  1  according to an embodiment of the present invention is described below with reference to  FIG. 4 .  FIG. 4  shows the state in which the connection adapter  1  includes the three communication modules  20 ,  25 , and  26 . During the operation, at least the communication module  20 ,  25 , or  26  can be included for practical use. 
     The connection adapter  1  includes in a housing  100  a primary control substrate  110 , a secondary control substrate  200  for loading the communication module  25  in accordance with the PDC standard, a secondary control substrate  300  for loading the communication module  20  in accordance with the CDMA standard, and the communication module  26  in accordance with the PHS standard. The secondary control substrates  200  and  300 , and the communication module  26  are provided as freely attached to and detached from the primary control substrate  110 . 
     The connection adapter  1  according to an embodiment of the present invention is provided with plural types of connectors for connection to the host device for connection to plural types of main control units. Practically, the primary control substrate  110  is provided with a connector  111  used in accordance with the RS-232C standard, a connector  112  used in accordance with the RS-485 standard, and a connector  113  used in accordance with the CAN (controller area network) standard. 
     A primary control substrate  110  is provided with a main control unit  120  implemented by an FPGA (field programmable gate array) as a type of PLD (programmable logic device), an interface circuit  131  in accordance with the RS-232C standard, an interface circuit  132  in accordance with the RS-485 standard, and an interface circuit  133  in accordance with the CAN standard. Each of the interface circuits  131 ,  132 , and  133  is interposed between the connectors  111 ,  112 , and  113  and the main control unit  120 . Thus, the main control unit  120  can communicate with the host device connected to the connectors  111 ,  112 , and  113  through each of the interface circuits  131 ,  132 , and  133 . 
     The primary control substrate  110  includes a connector  141  for connection with the secondary control substrate  200 , a connector  142  for connection with the secondary control substrate  300 , and a connector  143  for connection with the communication module  26  in accordance with the PHS standard. Each of the connectors  141 ,  142 , and  143  is connected to the main control unit  120 . Thus, the main control unit  120  can communicate with the communication module  25  in accordance with the PDC standard through the secondary control substrate  200 . Similarly, the main control unit  120  can communicate with the communication module  20  in accordance with the CDMA standard through the secondary control substrate  300 . The main control unit  120  can communicate directly with the communication module  26  in accordance with the PHS standard. 
     Furthermore, the primary control substrate  110  is provided with EPROM  151  storing a control program of the main control unit  120 , and RAM  152  for use as various work area of the main control unit  120 . Additionally, the primary control substrate  110  is provided with a module selection switch  160  for selection of the communication module  20 ,  25 , or  26 . The main control unit  120  performs an operation corresponding to the communication modules  20 ,  25 , and  26  selected by the module selection switch  160 . The configuration and the operation of the main control unit  120  are described later. 
     The primary control substrate  110  operates by external DC power supply. In addition, the primary control substrate  110  directly supplies DC power to the secondary control substrates  200  and  300 , and the communication module  26  of the PHS standard through each of the connectors  141 ,  142 , and  143 . The primary control substrate  110  is provided with a power supply monitor circuit  170  for monitoring external abnormal supply of DC power, and a backup battery  171 . When the power supply monitor circuit  170  detects external abnormal power supply, the circuit controls power supply from the backup battery  171  to the primary control substrate  110 , the secondary control substrates  200  and  300 , and the communication module  26  in accordance with the PHS. In addition, when the power supply monitor circuit  170  detects external abnormal power supply, it notifies the main control unit  120  of the abnormal power supply. Furthermore, when the power supply monitor circuit  170  detects the recovery of external power supply after abnormal power supply, it notifies the main control unit  120  of the recovery. 
     In addition, the primary control substrate  110  is provided with a circuit initializing unit  180  for initializing and generating the internal circuit of the main control unit  120  implemented by the FPGA. The circuit initializing unit  180  contains a program for initializing and generating an internal circuit of the main control unit  120 . The circuit initializing unit  180  forms a circuit configuring the main control unit  120  in the FPGA at an instruction from an externally connected terminal (not shown in the drawings). 
     The secondary control substrate  200  is to connect the primary control substrate  110  to the communication module  25  in accordance with the PDC standard. The secondary control substrate  200  is provided with a connector  201  for connection to the primary control substrate  110 , a connector  202  for connection to a terminal  25   a  of the communication module  25  in accordance with the PDC standard, and an interface circuit  210  for connection between the primary control substrate  110  and the communication module  25 . The interface circuit  210  converts the number of pins between the connector  202  and the connector  201 , converts the assignment of pins, forms a waveform, etc. The communication module  25  according to an embodiment of the present invention requires a predetermined memory chip storing its own telephone number information etc., and requires a dedicated backup battery. Correspondingly, the memory chip  220  and the backup battery  230  are connected to the communication module  25  of the secondary control substrate  200  through the connector  202 . The secondary control substrate  200  is operated by a DC power supply from the primary control substrate  110  as described above, and DC power is supplied to the communication module  25  through the connector  202 . An antenna connection terminal  25   b  of the communication module  25  is connected to an antenna connection terminal  191  provided for the housing  100 . 
     The secondary control substrate  300  is to connect the primary control substrate  110  to the communication module  20  in accordance with the CDMA standard. The secondary control substrate  300  is provided with a connector  301  for connection to the primary control substrate  110 , a connector  302  for connection to a terminal  20   a  of the communication module  20  in accordance with the CDMA standard, and an interface circuit  310  for connection of the primary control substrate  110  to the communication module  20 . The interface circuit  310  converts the number of pins between the connector  302  and the connector  301 , converts the assignment of pins, generates a waveform, etc. In addition, the secondary control substrate  300  is operated by the DC power supply from the primary control substrate  110  as described above, and supplies DC power to the communication module  20  through the connector  302 . An antenna connection terminal  20   b  of the communication module  20  is connected to an antenna connection terminal  192  provided for the housing  100 . 
     A terminal  26   a  of the communication module  26  in accordance with the PHS standard is connected to the connector  143  of the primary control substrate  110 . An antenna connection terminal  26   b  of the communication module  26  is connected to an antenna connection terminal  193  attached to a housing  100 . 
     Next, the configuration and the operation of the main control unit  120  are described below with reference to  FIG. 5 .  FIG. 5  is a block diagram showing the configuration of the main control unit  120 . Only the components related to the gist of the present invention are described, but others are omitted. 
     As shown in  FIG. 5 , the main control unit  120  includes a line control unit  121  for controlling the line such as establishing a line connection etc., a communication control unit  122  for controlling data communication on the line established by the line control unit  121 , an interface  123  with the host device  10 , and an interface  124  with the communication modules  20 ,  25 , and  26 . The line control unit  121  controls line connection by an AT command, and controls connection of an IP layer by the LCP (link control protocol) and the IPCP. The communication control unit  122  performs a converting process of an IP address included in the header of the IP layer in the data communication on the line established by the line control unit  121 . 
     The line control unit  121  and the communication control unit  122  switches the process depending on the communication modules  20 ,  25 , and  26  selected by a module selection switch  160 . In the present embodiment, the host device  10  is designed to directly connect the communication modules  25  and  26 . Therefore, when the communication module  25  or  26  is selected by the module selection switch  160 , the line control unit  121  and the communication control unit  122  do not perform a special process on the data between the host device  10  and the communication module  25  or  26 , but only pass the data. On the other hand, when the communication module  20  is selected, the line control unit  121  and the communication control unit  122  perform converting, passing, and discarding processes on the data between the host device  10  and the communication module  20  according to a predetermined rule. The data required for the data processing is stored in a set data storage unit  151   a  of the EPROM  151 . 
     The data stored in the set data storage unit  151   a  is described with reference to  FIG. 6 . As shown in  FIG. 6 , the set data storage unit  151   a  stores a set of a telephone number included in the connection request from the host device  10  and the information (connection destination information) required in the process of connecting to a connection destination corresponding to the telephone number. The connection destination information includes a call issue command (including a telephone number) for connection to the wireless packet communication network  40 , a fixed IP address of the host device  10 , authentication data required for connection to the wireless packet communication network  40 , and IP addresses of the connection destination routers  60  and  65 . The authentication data describes the information designating the connection destination LAN as a domain name. 
     Next, the routers  60  and  65  provided at the boundary point between the wireless packet communication network  40  and the in-house LANs  50  and  55  are described below with reference to  FIG. 7 . Since the routers  60  and  65  are different from each other only in setting information, the router  60  is described here.  FIG. 7  shows the configuration of the router. The router  60  includes, as shown in  FIG. 7 , a WAN side interface  61 , a LAN side interface  62 , a line control unit  63  for line control such as the establishment of line connection etc., a communication control unit  64  for control of data communications, a setting data storage unit  65  for storing data necessary for the operations by the communication control unit  64 , and a log storage unit  66  for storing the operation histories of the line control unit  63  and the communication control unit  64 . The line control unit  63  controls the connection of an IP layer in cooperation with the connection adapter  1  and the messaging server  42 . The communication control unit  64  converts an IP address included in the header of the IP layer on the line established by the line control unit  63 . The setting data storage unit  65  stores at least data required in converting an address in the communication control unit  64 . 
     As shown in  FIG. 8 , the setting data storage unit  65  stores a host device information table  65   a  listing sets of fixed IP addresses (fixed terminal IP addresses) assigned to the host device  10  and telephone numbers of the communication module  20  connected to the host device  10 . The fixed terminal IP address is assigned to the host device  10  when a network connection service of assigning the fixed IP address with reference to  FIG. 2  is used. The setting data storage unit  65  is provided with an address conversion table  65   b  for storing sets of IP addresses for the address conversion in the communication control unit  64  for each communication. Practically, as shown in  FIG. 9 , the address conversion table  65   b  stores sets of communication IDs as management information for identifying each communication and fixed terminal IP addresses and IP addresses (dynamic terminal IP addresses) dynamically assigned to the connection adapter  1  of the host device  10  having the fixed terminal IP address, and sets of the IP addresses of the managing computer  51  as a communication partner of the host device  10  and the WAN side IP addresses of the router  60 . Each entry of the address conversion table  65   b  is generated each time a communication is established between the managing computer  51  and the host device  10 , and is deleted upon completion of the communication. 
     Next, the communication procedure in this system is described below with reference to the attached drawings. First, before the description of the communication system according to an embodiment of the present invention, the communication procedure when the network connection service for the host device  10  and the first managing computer  51  is described below with reference to the attached drawings. As described above, since the host device  10  corresponds to the communication module  25  in accordance with the PDC standard and the first wireless packet communication network  45 , the connection adapter  1  does not perform any process on the data between the host device  10  and the communication module  25 . Also, the router  60  does not perform any special process. A similar operation is performed when the host device  10  is connected to the first in-house LAN  50  using the communication module  26  in accordance with the PHS standard and over the wireless packet communication network  46 . 
     First, the case in which communication is started for the managing computer  51  from the host device  10  is described below with reference to the sequence chart shown in  FIG. 10 . 
     In this example, the following contents are presumed. That is, assume that the telephone number ‘080AABB’ is assigned to the communication module  25  from the carrier. Assume that an IP address of 192.168.0.0/24 is distributed from the carrier, and the IP address 192.168.0.1 is assigned to the host device  10  connected to the wireless packet communication network  45  using the communication module  25 . Assume that the IP address of the managing computer  51  of the communication partner is 192.168.9.10. The communication module  25  is assumed to be connected to the relay device of the wireless packet communication network  45  by issuing a call at an ‘ATDT’ command to the telephone number ‘080CCDD’. 
     As shown in  FIG. 10 , when the host device  10  issues an ‘ATDT080CCDD’ command to the connection adapter  1  (step S 1 ), the line control unit  121  of the connection adapter  1  transfers the command to the communication module  25  as is (step S 2 ). The trigger of the issue of the call can be the time when an IP packet of the destination address: 192.168.9.10 is generated. At the AT command, the communication module  25  issues a call to the relay device in the wireless packet communication network  45  (step S 3 ). The relay device confirms the telephone number of the source communication module  25 , and rejects the connection from the terminal without a contract (step S 4 ). Upon receipt of the response ‘CONNECT’ indicating that a connection is completed at the circuit level through the communication module  25  (step S 5 ), the line control unit  121  of the connection adapter  1  transfers the response to the host device  10  (step S 6 ). 
     Next, the host device  10  starts the process to make a connection to the first in-house LAN  50  through the wireless packet communication network  45  by the PPP. Practically, a connection to the relay device of the wireless packet communication network  45  is established at the IP level through the LCP and the IPCP (step S 7  and S 8 ). The line control unit  121  of the connection adapter  1  bidirectionally passes the packet relating to the LCP and the IPCP. Thus, the host device  10  can communicate with the first in-house LAN  50  at the IP level. Therefore, the data communication using an upper protocol such as TCP/UDP etc. is started (step S 9 ). The relay device of the wireless packet communication network  45  relays only the IP packet whose address or the source IP address is included in the 192.168.0.0/28 (step S 10 ). 
     Next, the case where the communication is started on the host device  10  from the first managing computer  51  is described below with reference to the sequence chart shown in  FIG. 11 . 
     When the first managing computer  51  issues a connection request to a fixed IP address assigned in advance to the host device  10  to communicate with the host device  10  as a communication partner (step S 11 ), the network router  60  transmits the packet to the wireless packet communication network  40  according to the normal routing rule. Thus, the relay device of the wireless packet communication network  45  refers to the destination IP address of the packet, and makes connection to the communication module  25  of the telephone number corresponding to the IP address (step S 12 ). The communication module  25  notifies the connection adapter  1  of the reception of a call (step S 13 ). The connection adapter  1  relays the reception notification to the host device  10  (step S 14 ). Next, if the connection adapter  1  receives a response to the reception notification from the host device  10  (step S 15 ), it starts a connection establishing process by the PPP with the relay device. Practically, the connection adapter  1  establishes a connection at the IP level to the relay device of the wireless packet communication network  45  by the LCP and the IPCP (step S 16  and S 17 ). The line control unit  121  of the connection adapter  1  passes bidirectionally the packet relating to the LCP and the IPCP. As described above, the host device  10  and the in-house LAN  50  can communicate with each other at the IP level. Therefore, data communication can be performed between them using an upper protocol such as the TCP/UDP etc. Then, the network router  60  relays the connection request in step S 11  to the host device  10  (step S 18 ). Then, the network router  60  relays the response (step S 19 ) from the host device  10  to the managing computer  51  (step S 20 ). Thus, the communications can be present at the IP level between the host device  10  and the in-house LAN  50 , thereby starting the data communication using an upper protocol such as the TCP/UDP etc. (step S 21 ). The relay device of the wireless packet communication network  45  relays only the IP packets whose destinations or source IP addresses are included in 192.168.0.0/28 (step S 22 ). 
     Next, the case in which the communication module  20  and the wireless packet communication network  40  in accordance with the CDMA standard are used without reforming or changing the host device  10  or the first managing computer  51  is described below with reference to the attached drawings. 
     First, with reference to  FIGS. 12 to 14 , the case in which communications are started from the host device  10  to the first managing computer  51  is described.  FIGS. 12 and 13  are sequence charts when communications are started from the host device to the managing computer.  FIG. 14  is an explanatory view of the converting process of the IP address described at the header of the IP packet transmitted from the host device. 
     The following descriptions are assumed. That is, assume that the communication module  20  is assigned the telephone number of ‘080XXYY’ through a carrier. Also assume that the IP address of 172.16.0.0/28 is distributed from the carrier, and the host device  10  connected to the wireless packet communication network  40  is dynamically assigned one of the IP address 172.16.0.0/28 using the communication module  20 . In addition, assume that the router  60  is assigned the addresses of 172.16.0.14. It is assumed that the IP address of the managing computer  51  of the communication partner is 192.168.9.10. The communication module  20  is connected to the relay device  41  of the wireless packet communication network  40  by issuing an ‘ATD9999’ command. The relay device  41  authenticates a user by the PAP and designates a connection destination (first in-house LAN  50  in the present embodiment). 
     As shown in  FIG. 12 , when the host device  10  issues an ‘ATDT080CCDD’ command to the connection adapter  1  (step S 31 ), the line control unit  121  of the connection adapter  1  acquires the connection destination information from the set data storage unit  151   a  using the telephone number included in the command as a key (step S 32 ). Then, the line control unit  121  of the connection adapter starts a connection to the first in-house LAN  50  according to the connection destination information. Practically, the line control unit  121  of the connection adapter  1  converts the command into ‘ATD9999’, and transfers it to the communication module  20  (step S 33 ). The trigger of the issue of the command is the time when the IP packet addressed to 192.168.9.10 as shown in  FIG. 14  is generated, etc. At the AT command, the communication module  20  issues a call to the relay device  41  in the wireless packet communication network  40  (step S 34 ). Upon receipt of the response ‘CONNECT’ indicating that the connection has been completed at the line level through the communication module  20  (step S 35 ), the line control unit  121  of the connection adapter  1  starts the process of connecting the connection adapter  1  to the first in-house LAN  50  through the PPP. 
     First, the line control unit  121  of the connection adapter  1  starts an LCP negotiation with the relay device  41  of the wireless packet communication network  40  (step S 36 ). Next, the line control unit  121  of the connection adapter  1  performs a PAP authenticating process with the relay device  41  of the wireless packet communication network  40  (step S 37 ). The PAP authenticating process is not conceived by the host device  10  generated for the wireless packet communication network  45 . However, it is required when the wireless packet communication network  40  is used. Therefore, in the present embodiment, the connection adapter  1  performs the authenticating process for the host device  10 . When the authenticating process is completed, the line control unit  121  of the connection adapter  1  starts an IPCP negotiation between the connection adapter  1  and the relay device  41  of the wireless packet communication network  40  (step S 38 ). Thus, the IPCP negotiation is completed, and a dynamic IP address 172.16.0.X is assigned from the wireless packet communication network  40  to the line control unit  121  of the connection adapter  1 . The assigned dynamic IP address is stored in the storage means such as the RAM  152 . 
     When the PPP negotiation is completed, the line control unit  121  of the connection adapter  1  notifies the router  60  of the telephone number of the communication module  20  and a communication ID having a special value (for example, 0) indicating an issue from the host device  10  using a UDP packet (step S 39 ). The line control unit  63  of the router  60  that has received the notification from the connection adapter  1  registers an entry in the address conversion table  65   b  for the communication ID included in the notification. Practically, the communication ID included in the notification, the fixed terminal IP address acquired from the host device information table  65   a , the source IP address (=dynamic terminal IP address) of the packet storing the notification, a predetermined IP address of the first managing computer  51 , and the WAN side IP address of the router  60  are registered in the address conversion table  65   b . Thus, the address conversion table  65   b  stores necessary data for an address conversion in the communication. 
     Next, the line control unit  63  of the router  60  transmits a connection request ‘CONNECT’ in the IP layer to the managing computer  51  (step S 40 ). At this time, the source IP address of the IP packet uses the fixed IP address of the host device  10 . That is, the packet relating to the connection request is the prefetch of a connection request issued by the host device  10  in the processes in subsequent steps S 46  to S 49 . The IP addresses of the host device  10  and the first managing computer  51  are acquired with reference to the address conversion table  65   b.    
     Upon receipt of the response ‘ACCEPT’ to the connection request (step S 41 ), the line control unit  63  of the router  60  transmits a response including a communication ID to the connection adapter  1  as a response in step S 39  (step S 42 ). The destination IP address of the response received from the first managing computer  51  is a fixed IP address of the host device  10 . However, the line control unit  63  of the router  60  does not relay the packet to the wireless packet communication network  40  at this stage. 
     After receiving a response from the router  60 , the line control unit  121  of the connection adapter  1  transmits a response ‘CONNECT’ indicating that the connection has been completed at the line level (step S 43 ). Upon receipt of the response, the host device  10  starts the LCP negotiation and the IPCP negotiation (steps S 44  and S 45 ). A point to node here is that the line control unit  121  of the connection adapter  1  transmits a response to the host device  10 . Thus, the host device  10  views the connecting process as being performed with the wireless packet communication network  45  with reference to  FIG. 10 . 
     In the process above, the communication at the IP level can be performed between the host device  10  and the connection adapter  1 , and between the connection adapter  1  and the first managing computer  51 . Thus, the host device  10  transmits a connection request ‘CONNECT’ in the IP layer to the first managing computer  51  (step S 46 ). The connection request corresponds to the first packet of the data communication in step S 9  shown in  FIG. 10 . Therefore, the destination IP address is the IP address of the first managing computer  51 , and the source IP address is the fixed terminal IP address of the host device  10 . Upon receipt of the connection request, the line control unit  121  of the connection adapter  1  converts the destination IP address into the WAN side IP address of the router  60 , converts the source IP address into the dynamic terminal IP address assigned by the wireless packet communication network  40 , and transmits it to the router  60  (step S 47 ). The line control unit  63  of the router  60  transmits a response to the connection adapter  1  in response to the connection request (step S 48 ). After receiving the response, the line control unit  121  of the connection adapter  1  converts the destination IP address into the fixed terminal IP address of the host device  10 , converts the source IP address into the IP address of the first managing computer  51 , and transfers the result to the host device  10  (step S 49 ). 
     After the process above, the host device  10  determines that the connection to the first managing computer  51  has been completed, and starts the data communication to the first managing computer  51  (step S 50 ). The communication control unit  64  of the router  60  and the communication control unit  122  of the connection adapter  1  perform an address conversion on the header of the IP packet (steps S 51 , S 52 ). Practically, as shown in  FIG. 14 , the fixed terminal IP address (192.168.0.1) and the dynamic terminal IP address (172.16.0.X) are mutually converted, and the WAN side IP address (172.16.0.14) of the router  60  and the IP address (192.168.9.10) of the first managing computer  51  are mutually converted. After the process above, communications can be started from the host device  10  with the first managing computer  51 . 
     Next, the case in which communications are started from the first managing computer  51  of the first in-house LAN  50  to the host device  10  is described with reference to  FIGS. 15 to 17 .  FIGS. 15 and 16  show the sequence of the communication started from the managing computer, and  FIG. 17  is an explanatory view of the process of converting an address. 
     The first managing computer  51  issues a packet of a connection request ‘CONNECT’ addressed to the fixed terminal IP address assigned in advance to the host device  10  to communicate with the host device  10  as a communication partner (step S 71 ). The line control unit  63  of the router  60  returns a reply in response to the connection request to the first managing computer  51  on behalf of the host device  10  (step S 72 ). 
     Next, the line control unit  63  of the router  60  acquires a telephone number corresponding to the destination IP address of the connection request packet from the host device information table  65   a . Then, the line control unit  63  generates a communication ID to uniquely identify the communication, and registers the entry of the communication in the address conversion table  65   b . Then, the line control unit  63  transmits a message addressed to the acquired telephone number, that is, using the messaging service to the connection adapter  1  connected to the host device  10  (step S 73 ). The transmission of the message is performed by issuing a request to the messaging server  42  to transmit a message by the HTTP. In addition, the message to be transmitted includes the communication ID and the IP address and the domain name (example 1 in the present embodiment) of the first managing computer  51  as a connection requester. 
     After receiving the message, the line control unit  121  of the connection adapter  1  acquires connection destination information from the set data storage unit  151   a  using a domain name included in the message as a key (step S 74 ). Then, the line control unit  121  of the connection adapter starts a connecting process to the first in-house LAN  50  according to the connection destination information. Practically, the “ATD9999” command is transmitted to the communication module  20  (step S 75 ). At the AT command, the communication module  20  issues a call to the relay device  41  in the wireless packet communication network  40  (step S 76 ). Upon receipt of the response ‘CONNECT’ indicating that the connection has been completed at a line level through the communication module  20  (step S 77 ), the line control unit  121  of the connection adapter  1  starts the process of connecting the connection adapter  1  to the first in-house LAN  50  by the PPP. 
     First, the line control unit  121  of the connection adapter  1  starts the LCP negotiation between the wireless packet communication network  40  and the relay device  41  (step S 78 ). Next, the line control unit  121  of the connection adapter  1  performs a PAP authenticating process with the relay device  41  of the wireless packet communication network  40  (step S 79 ). Next, the line control unit  121  of the connection adapter  1  starts the IPCP negotiation between the connection adapter  1  and the relay device  41  of the wireless packet communication network  40  (step S 80 ). Thus, the IPCP negotiation is completed, and the wireless packet communication network  40  assigns a dynamic IP address 172.16.0.X to the line control unit  121  of the connection adapter  1 . The assigned dynamic IP address is stored in the storage means such as the RAM  152 . 
     When the PP negotiation is completed, the line control unit  121  of the connection adapter  1  transmits to the router  60  a communication ID received from the router  60  in a UDP packet (step S 81 ). The line control unit  63  of the router  60  transmits a response including a communication ID to the connection adapter  1  (step S 82 ), and registers the source IP address (=dynamic terminal IP address) of the packet storing the communication ID and the WAN side IP address of the router  60  in the address conversion table  65   b  for the communication ID received from the connection adapter  1 . Thus, the address conversion table  65   b  stores necessary data for an address conversion in the communication. 
     Next, the line control unit  63  of the router  60  relays the connection request packet in step S 71  to the connection adapter  1  (step S 83 ). At this time, the destination IP address of the connection request packet is converted into the dynamic terminal IP address of the connection adapter  1 , and the source IP address is converted into the WAN side IP address of the router  60 . Upon receipt of the connection request, the line control unit  121  of the connection adapter  1  notifies the host device  10  of the reception (step S 84 ). Upon receipt of the reception notification, the host device  10  notifies the connection adapter  1  of the response to the reception notification (step S 85 ), and starts the LCP negotiation and the IPCP negotiation (step S 86 , S 87 ). The point to note here is that the line control unit  121  of the connection adapter  1  returns a response to the host device  10 . Thus, the host device  10  views the connecting process being performed with the wireless packet communication network  45  with reference to  FIG. 11 . 
     When the PPP negotiation is completed, the line control unit  121  of the connection adapter  1  transfers the connection request packet received from the router  60  in step S 83  to the host device  10  (step S 88 ). At this time, the destination IP address of the connection request packet is converted into a fixed terminal IP address of the host device  10 . Upon receipt of the connection request packet, the host device  10  transmits a response to the connection adapter  1  (step S 89 ). The destination and source IP addresses of the response packet are acquired by exchanging the destination IP address with the source IP address of the connection request packet. The connection adapter  1  converts the source IP address into the dynamic terminal IP address of the connection adapter  1 , and transmits the result to the router  60  (step S 90 ). 
     After the process above, the host device  10  determines that the connection to the first managing computer  51  has been completed, and starts the data communication to the first managing computer  51  (step S 92 ). The communication control unit  64  of the router  60  and the communication control unit  122  of the connection adapter  1  perform address conversion on the header of the IP packet (steps S 93 , S 94 )). Practically, as shown in  FIG. 17 , the communication control unit  64  of the router  60  mutually convert the fixed terminal IP address (192.168.0.1) and the dynamic terminal IP address (172.16.0.X), and also mutually converts the WAN side IP address (172.16.0.14) of the router  60  and the IP address (192.168.9.10) of the first managing computer  51 . The communication control unit  122  of the connection adapter  1  mutually converts the fixed terminal IP address (192.168.0.1) and the dynamic terminal IP address (172.16.0.X). 
     The communication procedure used when a connection from the first managing computer  51  to the host device  10  is made through the wireless packet communication network  40  is described above, but a similar communication procedure is used when a connection is made from the second managing computer  56  of the second in-house LAN  55  to the host device  10 . That is, when communications are established from the second in-house LAN  55 , the router  60  includes a domain name (‘example 2’ in the present embodiment) corresponding to the second in-house LAN  55  in the message transmitted to the connection adapter  1 . Thus, the connection adapter  1  can acquire setting information corresponding to the second in-house LAN  55  from the set data storage unit  51  using the domain name as a key. 
     In the embodiment above, since a connection request including a telephone number is fixedly set, the host device  10  appropriately rewrites the connection destination information about the set data storage unit  151   a , thereby starting the communication from the host device  10  to the second managing computer  56 . 
     As described above in detail, in the system according to the present embodiment, the network connection service of assigning a dynamic IP address can be used without changing or improving the host device  10  and the first managing computer  51  that use the network connection service of assigning a fixed IP. To be more concrete, although the network connection service of assigning a dynamic IP address is operating, communications can be started from the first managing computer  51  to the host device  10 . In addition, the source IP address of a packet received by the first managing computer  51  is the fixed IP address assigned to the host device  10  in advance. Therefore, first the managing computer  51  can designate a communication partner although communications are started from the host device  10  to the first managing computer  51 . 
     In the system according to the present embodiment, although the host device  10  can be connected only to the first managing computer  51 , the device can communicate with the second managing computer  56 . That is, the host device  10  can communicate with any computer by appropriately setting the connection destination information stored in the set data storage unit  151 . 
     In addition, since the connection adapter  1  according to the present embodiment converts, discards, and passes data transmitted between the host device  10  and the communication modules  20 ,  25 , and  26  so that the data can be correctly processed in each equipment, various differences among the protocol service communication modules  20 ,  25 , and  26  in the wireless packet communication networks  40 ,  45 , and  46  can be appropriately absorbed. 
     Second Embodiment 
     The second embodiment of the present invention is described below with reference to the attached drawings. The point of the communication system according to the present embodiment different from the first embodiment is the mode of the network connection service in the wireless packet communication network  40 . Described below is the second embodiment different in the mode of the connection service from the first embodiment. 
     In this connection service, as with the first embodiment, an IP address is assigned to a connection terminal in the dynamic IP assigning technique. However, unlike the first embodiment, the IP address to be assigned to the connection terminal is predetermined. As shown in  FIG. 18 , an address management server  43  is provided in the wireless packet communication network  40 . The address management server  43  manages a list of the telephone number of a connection terminal and IP addresses distributed to the terminal having the telephone number. 
     Practically, as shown in  FIG. 19 , the address management server  43  is provided with an address correspondence table  43   a  describing the correspondence between a telephone number and an IP address. The address management server  43  provides a user with an interface for update of the address correspondence table  43   a.    
     In this connection service, the wireless packet communication network  40  acquires the telephone number of the connection terminal when a terminal is connected. Then, the IP address corresponding to the telephone number is acquired from the address correspondence table  43   a , and distributes the acquired IP address to the connection terminal. An IPCP is used in distributing the address. That is, in the present embodiment, a technique of dynamically assigning an IP called IPCD, but a distributed IP address is predetermined. 
     In this connection service, the wireless packet communication network  40  receives an IP packet addressed to the IP address corresponding to the terminal from the in-house LANs  50  and  55 , and when the terminal is not connected to the wireless packet communication network  40 , the messaging server  42  acquires the telephone number corresponding to the IP packet from the address management server  43 . The wireless packet communication network  40  transmits a message to the telephone number. The messaging service is not a network connection service using the TCP/IP, but is implemented through a unique protocol using a wireless communication network. The message includes the domain names of the source in-house LANs  50  and  55 , thereby allowing the terminal to recognize that there is a connection request from the in-house LANs  50  and  55 . 
     In the present embodiment, when the above-mentioned network connection service is used, the configuration and the operation of the router  60  and connection adapter  1  are different from those according to the first embodiment. First, the router  60  is described below. The address system of the network according to the present embodiment is similar to the system shown in  FIG. 3 . 
     In the first embodiment above, the router  60  is provided with the line control unit  63  and the communication control unit  64 . The line control unit  63  reports a connection request from the in-house LANs  50  and  55  using a short message. However, in the present embodiment, when a packet enters the wireless packet communication network  40  from the in-house LANs  50  and  55 , the wireless packet communication network  40  automatically transmits the message. Therefore, in the present embodiment, the line control unit  63  is not required. Also, in the first embodiment, since the IP address of the connection terminal is not constant, the communication control unit  64  of the router  60  performs an address converting process. However, in the present embodiment, since the IP address of the connection terminal is determined by the address management server  43 , the communication control unit  64  does not require the address converting process. Therefore, the communication control unit  64  of the router  60  only has to be provided with a common relaying function between the in-house LANs  50  and  55  and the wireless packet communication network  40 . That is, a general router  60  in the presumed communication system described with reference to  FIG. 2  can be used. 
     On the other hand, as in the first embodiment, the line control unit  121  of the connection adapter  1  performs line control such as establishment of line connection etc. In addition, the communication control unit  122  controls the data communication on the line established by the line control unit  121  as in the first embodiment. However, the line control unit  121  and the communication control unit  122  have an operation different from the operation according to the first embodiment in the above-mentioned network connection service. The operation of the connection adapter  1  is described later. 
     The communication procedure with the present system is described below with reference to the attached drawings. First, with reference to  FIGS. 20 and 21 , the case in which communications are started from the host device  10  to the first managing computer  51  is described.  FIG. 20  is a sequence chart when communications are started from the host device to the managing computer.  FIG. 21  is an explanatory view of the converting process of the IP address described at the header of the IP packet transmitted from the host device. 
     As shown in  FIG. 20 , when the host device  10  issues an ‘ATDT080CCDD’ command to the connection adapter  1  (step S 101 ), the line control unit  121  of the connection adapter  1  acquires connection destination information from the set data storage unit  151   a  using the telephone number included in the command as a key (step S 102 ). Then, the line control unit  121  starts the process of connecting to the first in-house LAN  50  according to the connection destination information. Practically, the line control unit  121  of the connection adapter  1  converts the command into ‘ATD9999’, and transfers it to the communication module  20  (step S 103 ). The trigger of the issue of the command is the time when the IP packet addressed to 192.168.9.10 as shown in  FIG. 21  is generated, etc. At the AT command, the communication module  20  issues a call to the relay device  41  in the wireless packet communication network  40  (step S 104 ). Upon receipt of the response ‘CONNECT’ indicating that the connection has been completed at the line level through the communication module  20  (step S 105 ), the line control unit  121  of the connection adapter  1  starts the process of connecting the connection adapter  1  to the first in-house LAN  50  through the PPP. 
     First, the line control unit  121  of the connection adapter  1  starts an LCP negotiation with the relay device  41  of the wireless packet communication network  40  (step S 106 ). Next, the line control unit  121  of the connection adapter  1  performs a PAP authenticating process with the relay device  41  of the wireless packet communication network  40  (step S 107 ). The PAP authenticating process is not conceived by the host device  10  generated for the wireless packet communication network  45 . However, it is required when the wireless packet communication network  40  is used. Therefore, in the present embodiment, the connection adapter  1  performs the authenticating process for the host device  10 . When the authenticating process is completed, the line control unit  121  of the connection adapter  1  starts an IPCP negotiation between the connection adapter  1  and the relay device  41  of the wireless packet communication network  40  (step S 108 ). Thus, the IPCP negotiation is completed, and a dynamic IP address 172.16.0.X is assigned from the wireless packet communication network  40  to the line control unit  121  of the connection adapter  1 . As described above, the present embodiment is quite different from the first embodiment in that the assigned IP address is predetermined for the communication module  20  as a connection terminal. The assigned dynamic IP address is stored in the storage means such as the RAM  152  etc. 
     When the PPP negotiation is completed, a response ‘CONNECT’ indicating that the connection has been completed at the line level is transmitted to the host device  10  (step S 109 ). The host device  10  receives the response, and starts LCP negotiation and the IPCP negotiation (steps S 110  and S 111 ). The point to note is that the line control unit  121  of the connection adapter  1  issues a response to the host device  10 . Thus, from the host device  10 , the connecting process is performed with the wireless packet communication network  45  as described above with reference to  FIG. 10 . 
     Since the connection between the host device  10  and the in-house LAN  50  is completed in the above-mentioned process, the host device  10  starts data communications to the managing computer  51  (step S 112 ). The communication control unit  122  of the connection adapter  1  performs an address conversion on the header of the IP packet (step S 113 ). Practically, as shown in  FIG. 11 , the fixed terminal IP address 192.168.0.1 and the dynamic terminal IP address 172.16.0.X are mutually converted. In the process above, the communication with the first managing computer  51  can be established and started from the host device  10 . 
     Next, the case in which communications are started from the first managing computer  51  of the first in-house LAN  50  to the host device  10  is described with reference to  FIGS. 22 and 24 .  FIGS. 22 and 23  are sequence charts of the communications to be started from the managing computer.  FIG. 24  is an explanatory view of the step of converting an address. 
     In this process, it is assumed that the IP address 172.16.0.1 is assigned in the address management server  43  to the communication module  20  connected to the host device  10 . 
     When the first managing computer  51  issues a connection request addressed to the IP address 172.16.0.1 of the communication module  20  connected to the host device  10  to communicate with the host device  10  as a communication partner (step S 151 ), the router  60  relays the packet to the wireless packet communication network  40  according to the normal routing rule (step S 152 ). 
     The wireless packet communication network  40  refers to the destination IP address of the packet received through the network router  60 , acquires the telephone number corresponding to the IP address from the address management server  43 , and then transmits a message that the connection request is received from the in-house LAN  50  to the telephone number through the messaging service (step S 153 ). As described above, the message includes a domain name (example 1 in the present embodiment) corresponding to the first in-house LAN  50 ). The wireless packet communication network  40  discards a packet relating to the connection request received through the router  60 . 
     The line control unit  121  of the connection adapter  1  that has received a message acquires connection destination information from the set data storage unit  151   a  using a domain name included in the message as a key (step S 154 ). Then, the line control unit  121  of the connection adapter  1  starts a connecting process to the first in-house LAN  50  on the basis of the connection destination information. Practically, it transmits an ‘ATD9999’ command to the communication module  20  (step S 155 ). At the AT command, the communication module  20  issues a call to the relay device  41  in the wireless packet communication network  40  (step S 156 ). Upon receipt of a response ‘CONNECT’ indicating that the connection has been completed at the line level through the communication module  20 , the line control unit  121  of the connection adapter  1  (step S 157 ), the process of connecting the connection adapter  1  to the first in-house LAN  50  is started by the PPP. 
     First, the line control unit  121  of the connection adapter  1  starts the LCP negotiation with the relay device  41  of the wireless packet communication network  40  (step S 158 ). Next, the line control unit  121  of the connection adapter  1  performs the PAP authenticating process with the relay device  41  of the wireless packet communication network  40  (step S 159 ). Next, the line control unit  121  of the connection adapter  1  starts the IPCP negotiation between the connection adapter  1  and the relay device  41  of the wireless packet communication network  40  (step S 160 ). Thus, the IPCP negotiation is completed, and a dynamic IP address 172.16.0.X is assigned to the line control unit  121  of the connection adapter  1  from the wireless packet communication network  40 . The present embodiment is quite different from the first embodiment in that the assigned IP address is predetermined to the communication module  20  as a connection terminal. The assigned dynamic IP address is stored in the storage means such as the RAM  152  etc. 
     When the PP negotiation is completed, a connection request packet from the first managing computer  51  reaches the connection adapter  1  (step S 161 ). As described above, the wireless packet communication network  40  has discarded the packet transmitted by the managing computer  51  in step S 151 . Therefore, the first managing computer  51  cannot receive a response of the connection request packet, and retransmits a connection request packet upon timeout. In addition, since some time is required for the processes in steps S 153  to S 159 , the retransmitted packet further reaches timeout. Therefore, the connection request packet reaching the connection adapter  1  is the latest packet in the packets retransmitted several times. 
     Upon receipt of the connection request packet from the first managing computer  51 , the line control unit  121  of the connection adapter  1  notifies the host device  10  of the reception (step S 162 ). Upon receipt of the reception notification, the host device  10  notifies the connection adapter  1  of the response to the reception notification (step S 163 ), and starts the LCP negotiation and the IPCP negotiation (steps S 164 , S 165 ). The point to note is a response to be transmitted from the line control unit  121  of the connection adapter  1  to the host device  10 . Thus, it seems to the host device  10  that the connecting process is being performed with the wireless packet communication network  45  described above with reference to  FIG. 11 . 
     When the PPP negotiation is completed, the line control unit  121  of the connection adapter  1  transfers the connection request packet received from the first managing computer  51  in step S 161  to the host device  10  (step S 166 ). Upon receipt of the connection request packet, the host device  10  returns a response to the connection adapter  1  (step S 167 ). The connection adapter  1  relays the response packet to the router  60  (step S 168 ). The router  60  relays the response packet to the first managing computer  51  according to the normal routing rule (step S 169 ). 
     In the process above, the host device  10  determines that the connection to the first managing computer  51  has been completed, and starts the data communication to the first managing computer  51  (step S 170 ). The communication control unit  122  of the connection adapter  1  performs an address conversion on the header of an IP packet (step S 171 ). Practically, as shown in  FIG. 24 , a fixed terminal IP address (192.168.0.1) and a dynamic terminal IP address (172.16.0.1) are mutually converted. 
     As described above in detail, in the communication system according to the present embodiment, the router  60  can be a common router, the configuration of the system can be easily prepared at a lower cost. Other advantages are the same as in the first embodiment. 
     The embodiments of the present invention have been described above in detail, but the present invention is not limited to the embodiments. For example, in the embodiments above, the router  60  acquires a dynamic IP address assigned to the connection adapter  1  by referring to the source IP address in the packet storing the notification received from the connection adapter  1 , but the dynamic IP address can be included in the notification. 
     The telemetring system for managing a vending machine is described in the embodiments above, but the present invention can be realized in other telemetring systems and telematics systems. 
     Also in the above-mentioned embodiment, the PDC standard, the CDMA standard, and the PHS standard are exemplified as communication modules, but other standards can be used in embodying the present invention. Similarly, any other interface standards on the host device side than those listed above can be applied. 
     Furthermore, in each of the above-mentioned embodiments, an authenticating method, an address system, an address assigning method (assigning a fixed IP address or a dynamic IP address) are exemplified as differences between the network connection service in the wireless packet communication networks  45  and  46  and the network connection service in the wireless packet communication network  40 . However, the present invention can be applied when a difference is one of them or a combination of them. Furthermore, other differences can be absorbed by the connection adapter as necessary. For example, in the above-mentioned embodiment, a PAP authentication is performed by the wireless packet communication network  40 . However, for example, when a connection is made to a communication network in which a CHAP (challenge handshake authentication protocol) authentication is performed, the CHAP can be implemented to the connection adapter. 
     Furthermore, in each of the above-mentioned embodiments, the connection adapter  1  can include three communication modules  20 ,  25 , and  26 , and each of the wireless packet communication networks  40 ,  45 , and  46  are arbitrarily available, but one of the communication modules  20 ,  25 , and  26  can be included and connected.