PURPOSE: To use a CRT keyboard to be controlled as a console or a work station according to a mode by adding a mode memory part and a work station control memory to a service processor.

CONSTITUTION: A service processor 6 contains a console control memory 61 to store a consol control program and a work station control memory 62 to store a work station control program. These memories 61 and 62 are switched according to the modes to support both console and work station modes. Both console control and work station control programs are stored to a floppy disk 8. The firmware which actuates CRT keyboards 21 and 22 as a console or a work station is stored in the disk 8 or a host file 9.