Patent ID: 7742051

Claim:
A data processing device connected with a data supply device for performing predetermined data processing, comprising: a communication control unit for controlling communication with the data supply device; a data processing unit for performing the data processing based on input data received from the data supply device; and a device control unit for performing predetermined processing in correspondence with command data received from the data supply device based on the command data, wherein: the communication control unit receives the input data and the command data each of which is contained in a packet having a common fixed length from the data supply device, and (a1) when an identification part at a predetermined position in the reception packet received from the data supply device is set at a predetermined command identification value indicating the command data, the communication control unit supplies data contained in the reception packet to the device control unit, and (a2) when the identification part is set at a value different from the command identification value, the communication control unit supplies data contained in the reception packet to the data processing unit; the device control unit uses the remaining part in the reception packet other than the identification part as the command data; and the data processing unit uses the remaining part as the input data.