Peripherals of computer

A peripheral for notifying a USB-connected upper apparatus of a device descriptor and allowing the upper apparatus to specify a communication partner destination by the function information shown in the device descriptor has: a peripheral function information holding unit which holds function information showing functions of the peripheral; a dependent peripheral function information holding unit which holds function information showing functions of a USB-connected dependent peripheral; and a USB control unit which reads out one of the function information held in those holding units by a selecting instruction and notifies the upper apparatus of the device descriptor in which the read-out function information is shown. A peripheral which can realize a multi-function without developing a dedicated driver and installing it into a PC is provided.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to peripherals which are connected to an upper apparatus through a USB (Universal Serial Bus) interface and, more particularly, to peripherals for realizing multi-function.

2. Related Background Art

An upper apparatus (hereinafter, referred to as a PC (personal computer)) having a USB-connecting function can be connected and disconnected to/from peripherals in the state where the PC operates (state where a power source is ON) and, further, can be connected in parallel to a plurality of peripherals. Therefore, since the USB-connection is easily detachable and a system can be relatively freely constructed, the USB-connection has been widespread. The peripheral added by the USB-connection is recognized by the PC at the moment when it is physically connected to the PC. The PC which recognized the peripheral searches for a driver of the recognized peripheral from drivers which it already has and makes device definition by the searched driver in order to control the peripheral.

As a connection control function of the peripheral mentioned above, an inserting/removing function of the peripherals called a “plug & play (PinP) function” has been known. The plug & play function is realized as will be explained hereinbelow. When the peripheral is USB-connected to the PC, the PC recognizes the USB-connected peripheral (device), automatically searches for a necessary device driver, and activates the corresponding driver, thereby enabling the added peripheral to be used. Specifically speaking, when the PC detects the USB-connection of the peripheral, a bus for USB-connecting the PC and the peripheral is reset, and after the bus resetting, the PC and the peripheral start communication called a “control transfer”.

In the control transfer, the peripheral notifies the PC of information called a device descriptor necessary for the device definition. Function information indicative of functions of the peripheral is shown in the device descriptor. The PC specifies the peripheral as a communication partner destination on the basis of the function information indicative of the functions of the peripheral shown in the device descriptor, makes the device definition for allocating an address called an “end point” to the specified peripheral, and starts USB-communication with the peripheral.

Multi-function peripherals (hereinbelow, referred to as MFP) having a plurality of functions such as scanner function, printer function, facsimile (FAX) function, and the like have been widespread as peripherals. Also in the case of USB-connecting the MFP to the PC and making USB-communication, the PC is notified of the device descriptor showing the plurality of functions provided for the MFP by the control transfer.

For example, as shown in JP-A-2001-222503, in order to select a desired function from the plurality of functions shown in the device descriptor, the PC which received the notification issues a switching command of a connecting construction (vendor request) called a “configuration” and makes the device definition.

In the conventional system, however, since the dedicated driver for selecting the desired function from the plurality of functions and issuing the switching command of the connecting construction is needed and it is necessary to develop such a dedicated driver and install it into the PC as mentioned above, they cause a problem.

SUMMARY OF THE INVENTION

It is, therefore, an object of the invention to provide peripherals which can realize multi-function without developing a dedicated driver and installing it into the PC.

According to the present invention, there is provided a peripheral for notifying a USB-connected upper apparatus of a device descriptor and allowing the upper apparatus to specify a communication partner destination on the basis of function information shown in the device descriptor, comprising:

a peripheral function information holding unit which holds function information indicative of functions of the peripheral;

a dependent peripheral function information holding unit which holds function information indicative of functions of a dependent peripheral which is USB-connected; and

a USB control unit which reads out either the function information held in the peripheral function information holding unit or the function information held in the dependent peripheral function information holding unit on the basis of a selecting instruction and notifies the upper apparatus of the device descriptor in which the read-out function information is shown.

In the present invention, the peripheral may be an image reading apparatus and the dependent peripheral may be an image forming apparatus. In this case, the peripheral function information holding unit holds the function information indicative of an image reading function, and the dependent peripheral function information holding unit holds the function information indicative of an image forming function.

Further, when the peripheral is an image forming apparatus and the dependent peripheral is an image reading apparatus, the peripheral function information holding unit holds the function information indicative of an image forming function, and the dependent peripheral function information holding unit holds the function information indicative of an image reading function.

In the present invention, the peripheral further comprises an operation panel which receives the selecting instruction, and wherein when the selecting instruction is received by the operation panel, the USB control unit executes bus resetting in the USB-connection with the upper apparatus before the notification of the device descriptor.

In the peripheral, the USB control unit has a multi-device descriptor forming unit which forms the device descriptor in which the function information which is read out based on the selecting instruction is contained.

Moreover, the peripheral may further comprise an original reading unit which reads an original, and wherein when it is detected that the original has been arranged, the original reading unit notifies the USB control unit of an original detection signal as the selecting instruction, and when the original detection signal is received, the USB control unit reads out the function information indicative of the image reading function.

Moreover, the peripheral may further comprise a timer which notifies the USB control unit of a left-original detection signal as the selecting instruction when it is detected that the original has been arranged and left, and wherein when the left-original detection signal is received, the USB control unit reads out the function information indicative of the image forming function.

Moreover, in the peripheral, the original reading unit reads out the arranged original and, when it is detected that there are no originals to be read, notifies the USB control unit of an end detection signal as the selecting instruction, and when the end detection signal is received, the USB control unit reads out the function information indicative of the image forming function.

Moreover, the peripheral may further comprise a specific information extracting unit which analyzes a control command from the upper apparatus and extracts specific information, and wherein when an instruction to execute bus resetting in the USB-connection with the upper apparatus is shown in the extracted specific information, the USB control unit executes the bus resetting.

Moreover, the peripheral may further comprise a specific information extracting unit which analyzes a control command from the upper apparatus and extracts specific information, and wherein when the specific information is a command described by a control language of an image reading apparatus, the specific information extracting unit notifies the USB control unit of the command as the selecting instruction, and when the command is received, the USB control unit reads out the function information indicative of the image reading function.

Moreover, the peripheral may further comprise a specific information extracting unit which analyzes a control command from the upper apparatus and extracts specific information, and wherein when the specific information is a command described by a control language of an image forming apparatus, the specific information extracting unit notifies the USB control unit of the command as the selecting instruction, and when the command is received, the USB control unit reads out the function information indicative of the image forming function.

Moreover, in the peripheral, when information showing that a process based on the command has been finished is received as the selecting instruction, on the basis of the command, the USB control unit reads out the other function information which is not read out.

Moreover, in the peripheral, the USB-connection with the upper apparatus is hot plug-in connection, bus resetting in the USB-connection is executed by the hot plug-in connection.

Further, according to the present invention, there is provided a peripheral for notifying a USB-connected upper apparatus of a device descriptor and allowing the upper apparatus to specify a communication partner destination on the basis of function information shown in the device descriptor, comprising:

a peripheral function information holding unit which holds function information indicative of functions of the peripheral;

a dependent peripheral function information holding unit which holds function information indicative of functions of a dependent peripheral which is USB-connected; and

a USB control unit which reads out either the function information held in the peripheral function information holding unit or the function information held in the dependent peripheral function information holding unit on the basis of a selecting instruction and notifies the upper apparatus of the device descriptor in which the read-out function information is contained,

wherein the USB control unit has a host control section which executes a relay for communicating between the upper apparatus and the dependent peripheral, when the dependent peripheral is specified as the communication partner destination by the upper apparatus.

Moreover, in the peripheral, the peripheral may be a scanner; the dependent peripheral may be a printer.

According to the invention, by notifying the upper apparatus of the device descriptor showing either the function information indicative of the functions of the peripheral or the function information indicative of the functions of the dependent peripheral which is USB-connected to the peripheral on the basis of the selecting instruction, the upper apparatus specifies the communication partner destination on the basis of the single function information since only one function information is shown in the device descriptor. Thus, the dedicated driver to issue the switching command of the connecting construction is unnecessary in the upper apparatus and troublesomeness to install the dedicated driver into the PC can be eliminated.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the invention will now be described in detail with reference to the drawings. In the following description, it is assumed that the same or corresponding component elements shown in the drawings which are used for explaining the embodiments are designated by the same reference numerals and their overlapped explanation is omitted as much as possible.

An image reading apparatus as a peripheral of the invention is a scanner apparatus10. As shown inFIG. 1, the scanner apparatus10is connected to a PC30as an upper apparatus through a USB cable41and further connected to an image forming apparatus (printer apparatus20) as a dependent peripheral through a USB cable42.

An essence of the invention will now be described.

In the scanner apparatus10of the invention, as shown inFIG. 2, function information indicative of functions of the scanner apparatus10and function information indicative of functions of the printer apparatus20which is USB-connected to the scanner apparatus have previously been held in a function information holding unit150. On the basis of a selecting instruction, the scanner apparatus10reads out only one of the function information held in the function information holding unit150. A device descriptor in which the read-out function information is shown is formed by a USB control unit113. The PC30is notified of the device descriptor. Thus, the PC30can specify a communication partner destination on the basis of one function information shown in the device descriptor. A dedicated driver to select the function and issue a switching command of a connecting construction (vendor request) is unnecessary.

In the subsequent embodiments, examples in which the function information is previously held and the device descriptor in which the read-out function information is shown is formed and notified to the PC30will be explained. It is also possible to construct in such a manner that the device descriptor in which the scanner function information indicating the functions of the scanner apparatus10is shown and the device descriptor in which the printer function information indicating the functions of the printer apparatus20is shown are previously held and the held device descriptor is selected on the basis of the selecting instruction and notified to the PC30.

As shown inFIG. 2, the scanner apparatus10is constructed by: a reading unit111for reading an original; an image processing unit112for executing an image process to the read-out image; the USB control unit113which functions as one of USB devices with respect to the PC30, functions as a hub (HUB) with respect to the printer apparatus20, and is used for making USB-communication in accordance with a USB protocol; an operation panel114having a plurality of keys for allowing the operator to execute the operation setting of the scanner apparatus10and the like; a compressing unit115for compressing data formed by reading the original; a copy control unit116for making the printer apparatus20operative on the basis of the data obtained by reading the original, thereby allowing the original to be copied; a PC scanner control unit117for controlling the operation as a scanner on the basis of a control command from the PC30; a PC print control unit118which makes control as a PC print for receiving the print data and the control command from the PC30, transferring the received data and control command to the printer apparatus20, and allowing the printer apparatus20to execute the printing; an image memory119which is used as a work area for holding the data obtained by reading the original and executing the image process and a compressing process; an initializing unit121for forming either a device descriptor for the scanner (hereinafter, referred to as a scanner device descriptor) or a device descriptor for the printer (hereinafter, referred to as a printer device descriptor) at the time of initialization and transmitting the formed device descriptor to the PC30; a key event delivery unit122for notifying a device control unit1131, which will be explained hereinafter, of the USB control unit113that an arbitrary key on the operation panel114has been depressed; and the function information holding unit150for holding the scanner function information and printer function information, which will be explained hereinafter.

A CPU120makes substantial control of each of the above-mentioned units on the basis of programs held in a ROM (not shown). For simplicity of explanation, the scanner apparatus10will be described with respect to each of the foregoing functional blocks.

As shown inFIG. 3, the printer apparatus20which is connected to the scanner apparatus10by the USB cable42has: an emulation unit201for analyzing a printer language; a USB control unit202for transmitting and receiving the print data and control command between the scanner apparatus10and the printer apparatus20by USB-communication; an image memory203for storing the print data; a printing unit204for controlling a print engine to execute the printing process; and a decompressing unit205for decompressing the compressed print data which is transmitted.

A CPU206makes substantial control of each of the above-mentioned units on the basis of programs held in the ROM (not shown). For simplicity of explanation, the printer apparatus20will be described with respect to each of the foregoing functional blocks.

As shown inFIG. 4, the USB control unit113of the scanner apparatus10is constructed by: the device control unit1131for functioning as one of the USB devices; and a host control unit1132for functioning as a hub.

The host control unit1132has: a Tx buffer (Tx Buff)11321for transmitting the data to the printer apparatus20; and an Rx buffer (Rx Buff)11322for receiving the data from the printer apparatus20.

The device control unit1131has: an Rx buffer (Rx Buff)11311for receiving the data from the PC30; a Tx buffer (Tx Buff)11312for transmitting the data to the PC30; and a multi-descriptor forming unit11313having a plurality of descriptor forming units (not shown) each for forming a device descriptor, which will be explained hereinafter. When the PC30and the printer apparatus20make the USB-communication, the data held in the Rx buffer11311is transferred to the Tx buffer11321and the data held in the Rx buffer11322is transferred to the Tx buffer11312.

When the operator presses the key (on the operation panel114) which instructs the USB-communication between the PC30and the printer apparatus20, a device descriptor in which the printer function information, which will be explained hereinafter, is shown is formed. The PC30is notified of the device descriptor. After that, the foregoing transfer control is made.

The multi-descriptor forming unit11313will now be described. As shown inFIG. 5, the multi-descriptor forming unit11313is constructed by: a resetting unit11314for executing bus resetting in the USB-connection; a scanner descriptor forming unit11315for forming a device descriptor for the scanner (hereinafter, referred to as a scanner device descriptor); and a printer descriptor forming unit11316for forming a device descriptor for the printer (hereinafter, referred to as a printer device descriptor).

To allow the PC30to control the scanner apparatus10by the scanner function, the scanner descriptor forming unit11315reads out the scanner function information from the scanner function information holding unit151in the function information holding unit150and forms the device descriptor in which the scanner function information is shown.

To allow the PC30to control the printer apparatus20by the printer function through the scanner apparatus10, the printer descriptor forming unit11316reads out the printer function information from the printer function information holding unit152in the function information holding unit150and forms the device descriptor in which the printer function information is shown. In this manner, the device descriptor is formed in accordance with the function to be controlled by the PC30. The formed device descriptor is notified to the PC after the bus resetting in the USB-connection. The PC which received the notification specifies the communication partner destination on the basis of the function information shown in the device descriptor (makes device definition).

When the selecting instruction is received from the operator, the operation panel114outputs a selection signal according to the instruction to the USB control unit113. The multi-descriptor forming unit11313of the USB control unit113which received the selection signal activates either the scanner descriptor forming unit11315or the printer descriptor forming unit11316on the basis of the selection signal. In other words, when the operator presses a use button of the scanner apparatus10by the operation panel114, the scanner descriptor forming unit11315is activated and, when he presses a use button of the printer apparatus20, the printer descriptor forming unit11316is activated.

The operation panel114for outputting the selection signal will now be described.

As shown inFIG. 6, the operation panel114of the scanner apparatus10has: an LCD display1141for allowing the operator to set the operation; a plurality of pressing keys1142; and a PC-scanner key1143.

In correspondence to depressed ones of the plurality of keys1142, the operation panel114outputs the selection signal (selection information) according to the pressed keys to the USB control unit113. On the basis of the received selection signal, the multi-descriptor forming unit11313in the USB control unit113selects either the scanner descriptor forming unit11315or the printer descriptor forming unit11316and activates the selected forming unit.

When the PC-scanner key1143is pressed, the operation panel114outputs a signal indicative of the PC-scan selection to the USB control unit113. When the selection signal of the PC-scanning function is received, the USB control unit113selects the scanner descriptor forming unit11315in the multi-descriptor forming unit11313and activates the scanner descriptor forming unit11315.

When the selecting instruction is made by the keys1142of the operation panel114or the PC-scanner key1143is pressed, information indicative of the key depression (selection signal and reset signal) is transmitted from the operation panel114to the key event delivery unit122. The key event delivery unit122which received the information transfers the information to the device control unit1131in the USB control unit113. The device control unit1131which received the information executes the bus resetting in the USB-connection by the resetting unit11314and forms the device descriptor by the multi-descriptor forming unit11313. When the bus resetting is executed, the communication between the PC30and the scanner apparatus10is started by the control transfer. The formed device descriptor is notified to the PC30.

In the control transfer, when an obtaining command of the device descriptor is issued from the PC30to the scanner apparatus10, the device descriptor formed by the scanner apparatus10is sent from the scanner apparatus10to the PC30. On the basis of the obtained device descriptor, the PC30allocates an address for accessing the scanner apparatus10to the scanner and makes the device definition. After that, the PC30communicates with the scanner apparatus10by using the set address.

The device descriptor is divided into a plurality of parts and transmitted from the scanner apparatus10to the PC30. First, main information of the device descriptor is transmitted from the scanner apparatus10to the PC30. After that, the PC30issues an obtaining request of detailed information of the device descriptor to the scanner apparatus10. The scanner apparatus10which received the request outputs the necessary detailed information to the PC30. Information regarding resources of the scanner apparatus10, for example, information such as using method of the pipe, ID (identification) code, and the like is included in the necessary detailed information. For example, the PC30searches for the device driver with reference to the ID code and activates the corresponding driver. When the setup of the scanner apparatus10is completed in this manner, the scanner apparatus10can provide the functions described in the device descriptor.

When the scanner apparatus10is hot plug-in connected to the PC30, the PC30detects the connection of the scanner apparatus10and, thereafter, executes the bus resetting. Since the operation after the bus resetting is similar to that of the contents mentioned above, its description is omitted here.

The initializing unit121of the scanner apparatus10has a function for arbitrarily notifying the PC30of the device descriptor upon initialization. Specifically speaking, as shown inFIG. 7, the initializing unit121has: a default device descriptor table1211in which the forming unit of the device descriptor (the scanner descriptor forming unit11315or the printer descriptor forming unit11316) is made to correspond to a table number; and a default device descriptor table value storing area1212in which the table numbers to refer to the table upon initialization have been stored.

A corresponding table1213in which the scanner descriptor forming unit11315is made to correspond to the table No. 1; and a corresponding table1214in which the printer descriptor forming unit11316is made to correspond to the table No. 2 are shown in the default device descriptor table1211.

An arbitrary table number has been stored in the default device descriptor table value storing area1212. The forming unit of the device descriptor to be notified to the PC30upon initialization is selected in accordance with the table number shown in the default device descriptor table value storing area1212.

The initializing operation of the scanner apparatus10will now be described with reference to a flowchart ofFIG. 8.

First, when the initializing process of the scanner apparatus is started by the initializing unit121(step S0801), the value in the default device descriptor table value storing area1212is discriminated (S0802). If it is equal to “1”, the activation of the scanner descriptor forming unit11315is selected by the default device descriptor table1211. Thus, the device descriptor in which the scanner function information is shown is formed by the scanner descriptor forming unit11315. After that, the scanner descriptor is transmitted to the PC30by the device control unit1131in the USB control unit113(S0805).

When the value in the default device descriptor table value storing area1212is equal to “2” (S0803), the activation of the printer descriptor forming unit11316is selected by the default device descriptor table1211. The device descriptor in which the printer function information is shown is formed by the printer descriptor forming unit11316. After that, the printer descriptor is transmitted to the PC30by the device control unit1131in the USB control unit113(S0804).

When the value in the default device descriptor table value storing area1212is not equal to “2”, it is regarded that the value in the default device descriptor table value storing area1212is illegal, and a message showing that the memory storage data has been broken is displayed on an LCD display of the operation panel114(S0806).

The operation when the scanner apparatus10to which the printer apparatus20has been connected is connected to the PC30by the hot plug-in will now be described with reference to a flowchart ofFIG. 9.

When the scanner apparatus10is connected to the PC30by the hot plug-in (S0901), the PC30recognizes the connection of the new device and executes the bus resetting of the USB. When the resetting from the PC30is detected (S0902), the scanner apparatus10activates the printer descriptor forming unit11316. The printer descriptor is formed by the printer descriptor forming unit11316.

The formed printer descriptor is transmitted from the scanner apparatus10to the PC30(S0903). The PC30which obtained the printer descriptor executes address designation and sets a configuration descriptor, an interface descriptor, and the like in accordance with a USB protocol (S0904). A pipe for a bulk transfer or isochronous transfer is established and the scanner apparatus10starts the USB-communication with the PC30as a printer by the pipe (S0905).

The printing operation which is executed by the printer apparatus20on the basis of the data formed by the PC30will now be described with reference to a flowchart ofFIG. 10. Explanation will be made on the assumption that the operator issues an instruction to control the printer apparatus20by the PC30by the operation panel114, the device descriptor in which the printer function information is shown is formed and notified to the PC30, and the device definition is made by the PC30.

By a printer driver installed in the PC30, an image process is executed to the formed data, a compressing process is executed thereto, and the compressed data is converted into a printer language, thereby forming print data. The print data is transmitted from the PC30to the scanner apparatus10through the USB cable41. When the USB control unit113of the scanner apparatus10receives the print data (S1001), the print data is stored into the Rx buffer11311of the device control unit1131(S1002).

The data stored in the Rx buffer11311of the device control unit1131is transferred to the Tx buffer11321of the host control unit1132by the CPU or hardware (S1003). Subsequently, the print data stored in the Tx buffer11321of the host control unit1132of the USB control unit113is transmitted to the printer apparatus20by the control of a host controller of the PC30(S1004). The printer apparatus20executes the printing process on the basis of the received print data (S1005).

The operation in the case of using the scanner apparatus10as a PC-scanner function will now be described with reference to a flowchart ofFIG. 11. When the operator presses the PC-scanner key1143on the operation panel114(S1101), information indicative of the depression of the PC-scanner key1143is transmitted to the USB control unit113by the key event delivery unit122, so that the scanner descriptor forming unit11315is selected by the USB control unit113. The selected scanner descriptor forming unit11315forms the scanner descriptor.

After that, when the bus resetting is executed by the resetting unit11314of the USB control unit113(S1102), the scanner apparatus10starts the communication with the PC30by the control transfer (that is, the USB control unit113transmits the scanner descriptor to the PC30) (S1103). On the basis of the scanner descriptor, the PC30obtains information called address designation, configuration descriptor, and interface descriptor and makes various settings (S1104). By the settings, a transmission path called a pipe for the bulk transfer or isochronous transfer is determined and the PC starts the USB-communication with the scanner apparatus10(S1105).

According to the scanner apparatus10in the embodiment 1, only one function information whose selection has been instructed is read out so as to make the USB-communication by the function whose selection has been instructed by the operator by the operation panel114and when the device descriptor in which only the function information is shown is formed, the PC30is notified of the device descriptor after the bus resetting. Thus, the PC30can specify the communication partner destination on the basis of the single function information shown in the notified device descriptor, make the device definition of the specified communication partner destination, and make the USB-communication.

Therefore, according to the scanner apparatus10in the embodiment 1, by notifying the PC30of the device descriptor in which only one function information is shown, the communication partner destination can be specified on the basis of the single function information shown in the device descriptor. The dedicated driver to select the function and issue a switching command of the connecting construction (vendor request) is unnecessary. Thus, there is no need to develop the dedicated driver and, naturally, the troublesomeness to install the dedicated driver into the PC30can be eliminated.

According to the scanner apparatus10in the embodiment 1, there is no need to provide a special IC chip for setting an end point into each of the scanner apparatus10and the printer apparatus20and an increase in manufacturing costs of the scanner apparatus10and the printer apparatus20can be suppressed.

Further, by the initializing unit121for fixing so as to always select the device descriptor for the printer (or scanner) and setting so as to transmit the device descriptor for the printer (or scanner) to the PC30, when the power source is turned on, the scanner apparatus10can be fixed to the PC-printer function (or PC-scanner function) and used. The user can use the function which has been set to a default without being aware of the setting of use of the scanner apparatus10.

When the scanner apparatus10is connected to the PC30by hot plug-in, by fixing so as to always form the device descriptor for the printer (or scanner) and transmitting the device descriptor for the printer (or scanner) to the PC30, at the time of hot plug-in, the scanner apparatus can be fixed to the PC-printer function (or PC-scanner function) and used. Therefore, the scanner apparatus10can be used without confusing the operator.

In the case of setting the scanner apparatus so as to operate as a PC-printer function at the time of initialization, power-on, or hot plug-in connection as well, by pressing the PC-scanner key1143on the operation panel114, the scanner apparatus can be used by switching from the PC-printer function to the PC-scanner function. The use efficiency of the operator can be improved.

Since a system construction of the embodiment 2 is similar to that of the embodiment 1 shown inFIG. 1, its explanation is omitted here.

As shown inFIG. 12, according to a scanner apparatus11in the embodiment 2, the functions of the construction of the scanner apparatus10in the embodiment 1 are changed and new functions are added. Specifically speaking, the construction of the scanner apparatus11in the embodiment 2 differs from that of the embodiment 1 with respect to the following component elements: a reading unit111′ for reading the original; a USB control unit113A; an original detection event delivery unit123for, when it is detected that the original has been put in the reading unit, transmitting information indicative of the detection to the device control unit1131of the USB control unit113A; a left-original detecting timer124for detecting that the state where the original has been put in the reading unit continued for a predetermined time or more; and a time-out event delivery unit125for, when a time-out signal is received from the left-original detecting timer124, transmitting information indicative of the detection of the left-original to the device control unit1131of the USB control unit113A.

The reading unit111′ has an original detecting unit1111for detecting that the original has been put. The original detecting unit1111transmits an original detection signal indicating that the original has been put to the original detection event delivery unit123and the left-original detecting timer124.

The original detection event delivery unit123which received the original detection signal transmits the information indicative of the detection of the original to the USB control unit113A. When the information indicative of the detection of the original is received, the USB control unit113A selects the scanner descriptor forming unit11315and transmits the scanner descriptor formed in the scanner descriptor forming unit11315to the PC30.

When the original detection signal is received, the left-original detecting timer124starts the time counting operation. When it is detected that the state where the original has been put in the reading unit continued for a predetermined time or more, the timer124transmits the time-out signal to the time-out event delivery unit125. The time-out event delivery unit125which received the time-out signal transmits the information indicative of the detection of the left-original to the device control unit1131of the USB control unit113A. When the information indicative of the detection of the left-original is received, the left-original to the device control unit1131of the USB control unit113A selects the printer descriptor forming unit11316and transmits the printer descriptor formed by the printer descriptor forming unit11316to the PC30.

The operation of the scanner apparatus11in the embodiment 2 will now be described with reference to a flowchart ofFIG. 13.

When the original is put in the reading unit111′ of the scanner apparatus11to use the scanner function by the operator, the original detecting unit1111detects that the original has been put (S1302) and outputs the original detection signal to the original detection event delivery unit123and the left-original detecting timer124. The left-original detecting timer124which received the original detection signal starts the time counting operation (S1303).

The original detection event delivery unit123which received the original detection signal transmits the information indicative of the detection of the original to the device control unit1131of the USB control unit113A (S1304). The device control unit1131which received the information indicative of the detection of the original selects the scanner descriptor forming unit11315and executes the bus resetting so as to transmit the scanner descriptor formed by the scanner descriptor forming unit11315to the PC30. By the control transfer after the bus resetting, the scanner descriptor is sent from the scanner apparatus11to the PC30(S1305).

The PC30makes the device definition on the basis of the obtained scanner descriptor. Thus, the PC30can recognize that the scanner apparatus11operates by the scanner function (S1306).

When the PC scan is not executed by the instruction of the operator in spite of the fact that the original has been put in the reading unit111′, if a time interval of, for example, 5 minutes has been set as a left-original detecting time, the left-original detecting timer124times out after the elapse of 5 minutes and outputs the time-out signal to the time-out event delivery unit125(S1307).

The time-out event delivery unit125which received the time-out signal outputs the information indicative of the detection of the left-original to the USB control unit113A (S1308). The device control unit1131of the USB control unit113A which received the information indicative of the detection of the left-original selects the printer descriptor forming unit11316by the multi-descriptor forming unit11313and transmits the printer descriptor formed by the printer descriptor forming unit11316to the PC30by the control transfer after the bus resetting (S1309).

The PC30makes the device definition on the basis of the obtained printer descriptor. Thus, the PC30can make the printer apparatus20operative through the scanner apparatus11.

According to the scanner apparatus11in the embodiment 2, the original detecting unit1111is provided for the reading unit111′ and, when it is detected that the original has been left, the USB control unit113A selects the scanner descriptor forming unit11315and transmits the scanner descriptor formed by the scanner descriptor forming unit11315to the PC30, so that the PC30can make the device definition on the basis of the scanner descriptor. Thus, merely by putting the original onto the scanner apparatus11, the PC-scanner function can be used and the use efficiency of the operator can be improved.

When the left-original detecting timer124detects the left-original, the function of the scanner apparatus11is switched to the PC-printer function. Therefore, when the original is left without reading the original by the reading unit111′, the operator can use the scanner apparatus11as a PC-printer function.

Since a system construction of the embodiment 3 is similar to that of the embodiment 1 shown inFIG. 1, its explanation is omitted here.

As shown inFIG. 14, according to a scanner apparatus12in the embodiment 3, the following component elements are added to the construction of the scanner apparatus11in the embodiment 2: a USB control unit113B in place of the USB control unit113A; a PC print control unit118′ for making control for the PC printer; and a printer simple emulation event delivery unit126for transmitting information indicative of detection of a command to switch the device descriptor from the printer descriptor to the scanner descriptor to the USB control unit113B.

The PC print control unit118′ has a printer simple emulation unit (specific information extracting unit)1181for analyzing the printer language sent from the PC30and detecting the “command to switch the device descriptor from the printer descriptor to the scanner descriptor” (specific information). When the “command to switch the device descriptor from the printer descriptor to the scanner descriptor” cannot be detected in the printer simple emulation unit (specific information extracting unit)1181, the ordinary PC-printer function is executed.

When a detection signal indicative of the detection of the “command to switch the device descriptor from the printer descriptor to the scanner descriptor” is received from the printer simple emulation unit1181, the printer simple emulation event delivery unit126transmits information indicative of the “command to switch the device descriptor” to the USB control unit113B.

The operation of the scanner apparatus12in the embodiment 3 will now be described with reference to a flowchart ofFIG. 15.

When the operator of the PC30issues an instruction to stop the PC-printer function from the PC30in order to use the scanner function, the printer driver transmits the command to switch the device descriptor from the printer descriptor to the scanner descriptor to the scanner apparatus12(S1501). When the scanner apparatus12which received the command detects the “command to switch the device descriptor from the printer descriptor to the scanner descriptor” in the printer simple emulation unit1181of the PC print control unit118′ (S1502), the printer simple emulation event delivery unit126is notified of the detection.

The printer simple emulation event delivery unit126which received the notification outputs information indicative of the detection of the “command to switch the device descriptor from the printer descriptor to the scanner descriptor” to the USB control unit113B (S1503). The device control unit1131of the USB control unit113B which received the information selects the scanner descriptor forming unit11315by the multi-descriptor forming unit11313and transmits the scanner descriptor formed by the scanner descriptor forming unit11315to the PC30by the control transfer after the bus resetting (S1504). The PC30makes the device definition on the basis of the obtained scanner descriptor. Thus, the PC30recognizes the scanner apparatus12as a scanner function and the PC-scanner function is validated.

According to the scanner apparatus12in the embodiment 3, when the printer language is analyzed by the printer simple emulation unit1181and the “command to switch the device descriptor from the printer descriptor to the scanner descriptor” is detected, by switching the device descriptor to the printer descriptor and notifying the PC30of the scanner descriptor, the PC30makes the device definition on the basis of the scanner descriptor and switches the connecting construction. Thus, by switching the apparatus from the PC-printer function to the PC-scanner function by the operation from the PC30, the apparatus can be used as a PC-scanner function and the use efficiency of the operator can be improved.

Since a system construction of the embodiment 4 is similar to that of the embodiment 1 shown inFIG. 1, its explanation is omitted here.

Although the “command to switch the device descriptor from the printer descriptor to the scanner descriptor” is detected in the scanner apparatus12in the embodiment 3, a scanner apparatus13in the embodiment 4 differs from the scanner apparatus12in the embodiment 3 with respect to a point that a “command to switch the device descriptor from the scanner descriptor to the printer descriptor” is detected.

As shown inFIG. 16, according to the scanner apparatus13in the embodiment 4, the following component elements are added to the construction of the scanner apparatus12in the embodiment 3: a USB control unit113C in place of the USB control unit113B; a PC scanner control unit117′ for making control for the PC printer; and a scanner simple emulation event delivery unit127for transmitting information indicative of detection of the command to switch the device descriptor from the scanner descriptor to the printer descriptor to the USB control unit113C.

The PC scanner control unit117′ has a scanner simple emulation unit (specific information extracting unit)1171for analyzing the scanner language sent from the PC30and detecting the “command to switch the device descriptor from the scanner descriptor to the printer descriptor” (specific information). When the “command to switch the device descriptor from the scanner descriptor to the printer descriptor” cannot be detected in the scanner simple emulation unit (specific information extracting unit)1171, the ordinary PC-scanner function is executed.

When a detection signal indicative of the detection of the “command to switch the device descriptor from the scanner descriptor to the printer descriptor” is received from the scanner simple emulation unit1171, the scanner simple emulation event delivery unit127transmits information indicative of the “command to switch the device descriptor” to the USB control unit113C.

The operation of the scanner apparatus13in the embodiment 4 will now be described with reference to a flowchart ofFIG. 17.

When the operator issues an instruction to stop the PC-scanner function from the PC30in order to use the printer function, the scanner driver transmits the command to switch the device descriptor from the scanner descriptor to the printer descriptor to the scanner apparatus13(S1701). When the scanner apparatus13which received the command detects the “command to switch the device descriptor from the scanner descriptor to the printer descriptor” in the scanner simple emulation unit1171of the PC scanner control unit117′ (S1702), the scanner simple emulation event delivery unit127is notified of the detection.

The scanner simple emulation event delivery unit127which received the notification outputs information indicative of the detection of the “command to switch the device descriptor from the scanner descriptor to the printer descriptor” to the USB control unit113C (S1703). The device control unit1131of the USB control unit113C which received the information selects the printer descriptor forming unit11316by the multi-descriptor forming unit11313and transmits the printer descriptor formed by the printer descriptor forming unit11316to the PC30by the control transfer after the bus resetting (S1704). The PC30makes the device definition on the basis of the obtained printer descriptor. Thus, the PC30can make USB-communication with the printer apparatus20through the scanner apparatus12.

According to the scanner apparatus13in the embodiment 4, when the scanner language is analyzed by the scanner simple emulation unit1171and the “command to switch the device descriptor from the scanner descriptor to the printer descriptor” is detected, by switching the device descriptor to the scanner descriptor and notifying the PC30of the printer descriptor, the PC30makes the device definition on the basis of the printer descriptor and switches the connecting construction. Thus, by switching the apparatus from the PC-scanner function to the PC-printer function by the operation from the PC30, the apparatus can be used as a PC-printer function and the use efficiency of the operator can be improved.

Since a system construction of the embodiment 5 is similar to that of the embodiment 1 shown inFIG. 1, its explanation is omitted here.

As shown inFIG. 18, according to a scanner apparatus14in the embodiment 5, the following component elements are added to the construction of the embodiment 4: a USB control unit113D in place of the USB control unit113C; a PC scan operation end event delivery unit128for transmitting information indicative of the end of the PC scanner function to the USB control unit113D; and a PC print operation end event delivery unit129for transmitting information indicative of the end of the PC-printer function to the USB control unit113D.

When the end of the PC scanning operation is detected by the reading unit111′, the PC scan operation end event delivery unit128transmits PC scan end information to the device control unit1131of the USB control unit113D.

When it is detected that all of the print data stored in the Tx buffer11321of the host control unit1132of the scanner apparatus14has been transmitted to the printer apparatus20, the PC print operation end event delivery unit129transmits the PC print end information to the device control unit1131of the USB control unit113D.

When PC scan end information is received, the device control unit1131of the USB control unit113D selects the printer descriptor forming unit11316by the multi-descriptor forming unit11313and transmits the printer descriptor formed by the printer descriptor forming unit11316to the PC30. The device control unit1131which received the PC print end information selects the scanner descriptor forming unit11315by the multi-descriptor forming unit11313and transmits the scanner descriptor formed by the scanner descriptor forming unit11315to the PC30.

The operation of the scanner apparatus14will now be described.

The operation when the PC-scanner function has been selected will be described with reference to a flowchart ofFIG. 19.

The end of the PC scanning operation is monitored in the reading unit111′ (S1902). When the end of the PC scanning operation is detected by the reading unit111′, the PC scan operation end event delivery unit128is notified of the PC scan end information. The PC scan operation end event delivery unit128transmits information indicative of the end of the PC scanning operation to the USB control unit113D (S1903).

The device control unit1131of the USB control unit113D which received the PC scanning operation end information selects the printer descriptor forming unit11316from the two descriptor forming units by the multi-descriptor forming unit11313and transmits the printer descriptor formed by the selected printer descriptor forming unit11316to the PC30by the control transfer after the bus resetting was executed (S1904). Since the subsequent operation is similar to the contents described in the foregoing embodiment, its explanation is omitted here. The PC printing function is validated after similar processing steps are executed.

The operation when the PC-printer function has been selected will now be described with reference to a flowchart ofFIG. 20.

The end of the PC printing operation is monitored (S2002). The PC print operation end event delivery unit129which detected the end of the PC printing operation transmits information indicative of the end of the printing operation to the USB control unit113D (S2003).

The device control unit1131of the USB control unit113D which received the PC printing operation end information selects the scanner descriptor forming unit11315from the two descriptor forming units by the multi-descriptor forming unit11313and transmits the scanner descriptor formed by the selected scanner descriptor forming unit11315to the PC30by the control transfer after the bus resetting was executed (S2004). Since the subsequent operation is similar to the contents described in the foregoing embodiment, its explanation is omitted here. The PC scanning function is validated after similar processing steps are executed.

According to the scanner apparatus14in the embodiment 5, when the end of the PC scanning operation is detected, the device control unit1131of the USB control unit113D forms the device descriptor for allowing the scanner apparatus to function as a PC printing operation on the basis of the information from the PC scan operation end event delivery unit128and notifies the PC30of the device descriptor. When the end of the PC printing operation, the device control unit1131of the USB control unit113D forms the device descriptor for allowing the scanner apparatus to function as a PC scanning printing operation on the basis of the information from the PC print operation end event delivery unit129and notifies the PC30of the device descriptor. For example, by presetting the function which is mainly used by the operator as a function to be made operative after completion of the function, when a desired function is finished, the function can be automatically switched to the function which is mainly used by the operator. The use efficiency of the operator can be improved.

The foregoing embodiment has been described with respect to the system, as an example, in which the scanner apparatus is USB-connected as a peripheral and the printer apparatus is USB-connected as a dependent peripheral. An embodiment 6 will now be described with respect to a system constructed in such a manner that, as shown inFIG. 21, a printer apparatus60is connected as a peripheral to a PC80through a USB cable91and a scanner apparatus70is connected as a dependent peripheral to the printer apparatus60through a USB cable92.

As shown inFIG. 22, the printer apparatus60has: a printing unit601for printing onto a sheet; a decompressing unit602for decompressing compressed print data; a USB control unit603which functions as one of the USB devices with respect to the PC80, functions as a hub with respect to the scanner apparatus70, and is used to make USB-connection in accordance with a USB protocol; an operation panel604on which a plurality of keys for making operation setting of the printer apparatus60by the operator and the like are provided; an emulation unit605for decoding a printer control language; a PC scanner control unit606which temporarily receives a control command for the PC scanner by the printer apparatus60, transfers the received control command to the scanner apparatus70, and is used to control the scanner apparatus so as to function as a PC scanner; a PC print control unit607for controlling the apparatus so as to function as a PC printer; an image memory609which is used as a work area for holding the print image data and executing the image process and the compressing process; an initializing unit610for forming the device descriptor of either the scanner device descriptor or the printer device descriptor at the time of initialization and transmitting the formed device descriptor to the PC80; a key event delivery unit608for notifying a device control unit6031, which will be explained hereinafter, of the USB control unit603that an arbitrary key on the operation panel604has been depressed; and a function information holding unit650for holding the printer function information and the scanner function information.

A CPU611makes substantial control of each of the above-mentioned units on the basis of the programs held in the ROM (not shown). For simplicity of explanation, the printer apparatus60will be described with respect to each of the foregoing functional blocks.

The function information holding unit650of the printer apparatus601has: a scanner function information holding unit651for holding the function information indicative of the functions of the scanner apparatus70; and a printer function information holding unit652for holding the function information indicative of the functions of the printer apparatus60. Either the function information held in the scanner function information holding unit651or the function information held in the printer function information holding unit652is read out when the device descriptor, which will be explained hereinafter, is formed.

As shown inFIG. 23, the USB control unit603of the printer apparatus60is constructed by: the device control unit6031for functioning as one of the USB devices; and a host control unit6032for functioning as a hub.

The host control unit6032has: a Tx buffer (Tx Buff)60321for transmitting the data to the scanner apparatus70; and an Rx buffer (Rx Buff)60322for receiving the data from the scanner apparatus70.

The device control unit6031has: an Rx buffer (Rx Buff)60311for receiving the data from the PC80; a Tx buffer (Tx Buff)60312for transmitting the data to the PC80; and a multi-descriptor forming unit60313having a plurality of descriptor forming units (not shown) each for forming a device descriptor, which will be explained hereinafter. When the PC80and the scanner apparatus70make the USB-communication, the data held in the Rx buffer60311is transferred to the Tx buffer60321and the data held in the Rx buffer60322is transferred to the Tx buffer60312.

When the operator presses the key (on the operation panel604) which instructs the USB-communication between the PC80and the scanner apparatus70, a device descriptor in which the scanner function information, which will be explained hereinafter, is shown is formed. The PC80is notified of the device descriptor. After that, the foregoing transfer control is made.

The multi-descriptor forming unit60313will now be described. As shown inFIG. 24, the multi-descriptor forming unit60313is constructed by: a resetting unit60314for executing bus resetting in the USB-connection; a scanner descriptor forming unit60315for forming a scanner device descriptor; and a printer descriptor forming unit60316for forming a printer device descriptor.

To allow the PC80to control the scanner apparatus70by the scanner function through the printer apparatus60, the scanner descriptor forming unit60315reads out the scanner function information from the scanner function information holding unit651in the function information holding unit650and forms the device descriptor in which the scanner function information is shown.

To allow the PC80to control the printer apparatus60by the printer function, the printer descriptor forming unit60316reads out the printer function information from the printer function information holding unit652in the function information holding unit650and forms the device descriptor in which the printer function information is shown. In this manner, the device descriptor is formed in accordance with the function to be controlled by the PC80. The formed device descriptor is notified to the PC after the bus resetting in the USB-connection. The PC which received the notification specifies the communication partner destination on the basis of the function information shown in the device descriptor (makes device definition).

As shown inFIG. 25, the operation panel604of the printer apparatus60has: an LCD display6041for allowing the operator to set the operation; a plurality of pressing keys6042; and a PC-scanner key6043.

In correspondence to depressed ones of the plurality of keys6042, the operation panel604outputs the selection signal (selection information) according to the pressed keys to the USB control unit603. On the basis of the received selection signal, the multi-descriptor forming unit60313in the USB control unit603selects either the scanner descriptor forming unit60315or the printer descriptor forming unit60316and activates the selected forming unit. In other words, when the operator presses a use button of the scanner apparatus70by the operation panel604, the scanner descriptor forming unit60315is activated. When he presses a use button of the printer apparatus60, the printer descriptor forming unit60316is activated.

When the PC-scanner key6043is pressed, the operation panel604outputs a signal indicative of the PC-scan selection to the USB control unit603. The USB control unit603which received the selection signal indicative of the selection of the PC-scanning function selects the scanner descriptor forming unit60315in the multi-descriptor forming unit60313, activates the scanner descriptor forming unit60315, and forms the device descriptor. The PC80is notified of the formed device descriptor after the bus resetting in the USB-connection is executed in the resetting unit60314. Since the operation after the bus resetting is similar to that in the foregoing embodiment, its description is omitted here.

The initializing unit610of the printer apparatus60has a function for arbitrarily notifying the PC80of the device descriptor at the time of the initialization. As shown inFIG. 26, the initializing unit610has: a default device descriptor table6101in which the forming unit of the device descriptor (the scanner descriptor forming unit60315or the printer descriptor forming unit60316) is made to correspond to a table number; and a default device descriptor table value storing area6102in which the table numbers to refer to the table upon initialization have been stored.

A corresponding table6103in which the scanner descriptor forming unit60315is made to correspond to the table No. 1 and a corresponding table6104in which the printer descriptor forming unit60316is made to correspond to the table No. 2 are shown in the default device descriptor table1211.

An arbitrary table number has been stored in the default device descriptor table value storing area6102. The forming unit of the device descriptor to be notified to the PC80upon initialization is selected in accordance with the table number shown in the default device descriptor table value storing area6102.

The initializing operation of the initializing unit610of the printer apparatus60in the embodiment 6 will now be described with reference to a flowchart ofFIG. 27.

First, when the initializing process of the scanner apparatus is started by the initializing unit610(step S2701), the value in the default device descriptor table value storing area6102is discriminated (S2702). If it is equal to “1”, the activation of the scanner descriptor forming unit60315is selected by the default device descriptor table6101. Thus, the device descriptor in which the scanner function information is shown is formed by the scanner descriptor forming unit60315. After that, the scanner descriptor is transmitted to the PC80by the device control unit6031in the USB control unit603(S2705).

When the value in the default device descriptor table value storing area6102is equal to “2” (S2703), the activation of the printer descriptor forming unit60316is selected by the default device descriptor table6101. The device descriptor in which the printer function information is shown is formed by the printer descriptor forming unit60316. After that, the printer descriptor is transmitted to the PC80by the device control unit6031in the USB control unit603(S2704).

When the value in the default device descriptor table value storing area6102is not equal to “2”, it is regarded that the value in the default device descriptor table value storing area6102is illegal, and a message showing that the memory storage data has been broken is displayed on the LCD display6041of the operation panel604(S2706).

The operation when the printer apparatus60to which the scanner apparatus70has been connected is connected to the PC80by the hot plug-in will now be described with reference to a flowchart ofFIG. 28.

When the scanner apparatus70is connected to the PC80by the hot plug-in (S2801), the PC80recognizes the connection of the new device and executes the bus resetting of the USB by the resetting unit60314. When the resetting from the PC80is detected (S2802), the printer apparatus60activates the printer descriptor forming unit60316. The printer descriptor is formed by the printer descriptor forming unit60316.

The formed printer descriptor is transmitted from the printer apparatus60to the PC80by the control transfer (S2803). The PC80which obtained the printer descriptor executes the address designation and sets the configuration descriptor, the interface descriptor, and the like in accordance with the USB protocol (S2804). A pipe for a bulk transfer or isochronous transfer is established and the printer apparatus60starts the USB-communication with the PC80as a printer device by the pipe (S2805).

The operation when the operator uses the printer apparatus60by the scanner function will now be described with reference to a flowchart ofFIG. 29.

When the PC-scanner key6043on the operation panel604is pressed by the operator (S2901), the key event delivery unit608notifies the USB control unit603of information showing that the PC-scanner key6043has been depressed. The USB control unit603which received the information selects the scanner descriptor forming unit60315. The selected scanner descriptor forming unit60315forms the scanner descriptor.

After that, when the bus resetting is executed by the resetting unit60314of the device control unit6031(S2902), the printer apparatus60starts the communication with the PC80by the control transfer. That is, the device control unit6031of the printer apparatus60transmits the scanner descriptor to the PC80(S2903). The PC80obtains the information called address designation, configuration descriptor, and interface descriptor and makes various settings on the basis of the scanner descriptor (S2904). By this setting, the transmission path called a pipe for the bulk transfer or isochronous transfer is determined. The printer apparatus60starts the USB-communication with the PC80as a printer device by the pipe (S2905).

According to the printer apparatus60in the embodiment 6, only one function information whose selection has been instructed is read out so as to make the USB-communication by the function whose selection has been instructed by the operator through the operation panel604. When the device descriptor in which only such function information is shown is formed, the PC80is notified of this device descriptor after the bus resetting. Thus, the PC80can specify the communication partner destination on the basis of the single notified function information shown in the device descriptor, makes the device definition of the specified communication partner destination, and can make the USB-communication.

Therefore, according to the printer apparatus60in the embodiment 6, by notifying the PC80of the device descriptor in which only one function information is shown, the communication partner destination can be specified on the basis of the single function information shown in the device descriptor and the dedicated driver to select the function and issue the switching command of the connecting construction (vendor request) is unnecessary. Therefore, there is no need to develop the dedicated driver and, naturally, the troublesomeness to install the dedicated driver into the PC80can be eliminated.

Although the embodiments have been described by limiting the peripherals to the printer apparatus and scanner apparatus, the invention is not limited to them.

The invention can be applied to, for example, a monitor apparatus, a keyboard, a mouse, a facsimile apparatus, a storing device, an image server apparatus, and the like as peripherals.

Although the embodiments are not described with respect to the updating of the function information held in the function information holding unit150of the peripheral, for example, it is possible to construct the apparatus in such a manner that when the dependent peripheral is connected to the peripheral, the function information is obtained from the dependent peripheral, and the function information held in the function information holding unit150is updated or that the function information is obtained by communicating with an upper apparatus and the function information held in the function information holding unit150is updated. The function information held in the function information holding unit150can be also updated by exchanging a ROM in the peripheral.

The foregoing embodiments have been described with respect to the example in which the function information of the peripheral and the function information of the dependent peripheral are preliminarily held in the function information holding unit150of the peripheral, one of the function information is read out as necessary, and the device descriptor is formed and notified to the upper apparatus. However, the invention is not limited to such an example. For instance, it is possible to construct the apparatus in such a manner that the device descriptor for the peripheral and the device descriptor for the dependent peripheral are preliminarily held and the upper apparatus is notified of one of the device descriptors in accordance with the selecting instruction.

Although the foregoing embodiments have been described with respect to the initializing unit as an example in which the forming unit of the device descriptor is selected on the basis of the table number, the invention is not limited to such an example. For instance, the device descriptor can be also made to correspond to the table number. By this method, even if the device descriptor is not formed, the upper apparatus can be directly notified of the device descriptor which has been made to correspond to the table number.

The present invention is not limited to the foregoing embodiments but many modifications and variations are possible within the spirit and scope of the appended claims of the invention.