Outside attaching keyboard joint verification device

摘要

PURPOSE:To confirm whether an outside attached keyboard is connected or not without fail by judging whether any synchronizing clocks are transmitted from the outside attached keyboard or not. CONSTITUTION:A first keyboard 17 is mounted as a standard, and a second outside attached keyboard 19 is made arbitrarily connectable to a personal computer. A CPU 1 issues an initializing command to the outside attached keyboard 19. A control means 11 receives the initializing command and transmits a data transmission request signal to the outside attached keyboard 19. Next, a judging means 11 judges whether the synchronizing clock signal is detected from the outside attached keyboard 19 or not. Based on the judged result of the judging means 11, it is judged whether the outside attached keyboard 19 is connected or not.