PURPOSE: To obtain the corresponding and proper conversion code in a simple constitution based on the input information of the operation input part by allotting the code conversion table region to the firmware.

CONSTITUTION: Firmware P-ROM104 storing the microprogram is connected to microprocessor 3, and each region of microprogram 104A and code conversion table 104B is allotted to P-ROM104. With operation of a certain key Ki at operation input part 101, corresponding key input code K.No.i is sent to microprocessor 103 via I/O controller 102. With this control, the microprogram for the key input process is read out from P-ROM104, and the key input code is added to the head address of table 104B to obtain the address. Based on this address, table 104B is read to deliver the conversion code.