When power is on and a system floppy (14, 15) is in a disc drive (11e), loading firmware (F1) reads the system program name from a predetermined memory region of the system floppy. Based on said system program name, the firmware checks whether the system program is for a keyboard (K1) having a load key (LK); if ''YES'' the system program in the system floppy (14) is read into a RAM (11c) provided the load key is depressed, and if ''NO'' the system program in the system floppy (15) is read into the RAM regardless of the load key. Thereafter, under the control of said system program a keyboard control firmware (K2) converts the data input from the keyboards (K1, K2) into a code based upon the data conversion software corresponding to said keyboard.