| 摘要 |
<p>A control circuit for an operating panel in a printing apparatus or the like is provided with indicator devices and switches, and is adapted for lighting the indicator elements and sensing switching conditions of the switches on the basis of a control signal transmitted from a control unit. The control circuit is provided with a serial-to-parallel converter (2 in FIG. 2; 11 in FIG. 5) having input terminals (DATA, CLK) and output terminals (O1-O16) for converting a serial signal transmitted from the control unit (4, 5 in FIG. 2; 13 in FIG. 5) into a parallel signal. The output terminals (O1 - O16) of the serial-to-parallel converter are connected with the indicator elements (LED 1 - LED 16), which are put to the ground at the other ends thereof, and some output terminals (O9 - O16) of the serial-to-parallel converter are further connected with the switches (SW 1 - SW 8). <IMAGE></p> |
