PURPOSE: To reduce the number of signal lines between a detection part and a coordinate indicator by coding a switch signal from a code inputting switch, serially transmitting the coded signal, and serially transmitting also a status display signal.
CONSTITUTION: Signals from respective switches of the code inputting switch 6 in the coordinate indicator 5 are converted into codes by a decoder 9, the codes are stored in a shift register 10 and successively extracted in each bit, and respectively extracted signals are serially outputted as codes. On the other hand, status display signals generated from a detection part 1 to a display device 7 in parallel are successively extracted in each bit, and stored in a shift register 11, respective stored bit signals are allowed to correspond to respective display devices and said operation is controlled by clock signals and loading signals. Even if the number of switches in the code input switch 6 or the number of display devices in the status display device 7 is increased, the detection part 1 can be connected to the indicator 5 only through four signal lines in addition to an AC feeding conductor.
SAKATA MASATOSHI
NAKANO SEIICHI
