| 摘要 |
PURPOSE:To detect automatically a connection by a scanning circuit in case a keyboard is connected, by setting it to the same state as a switch connection of one piece of diode. CONSTITUTION:A diode 912 is always placed so as to be connected to a wiring of X and Y axes. As a result, a signal (a) always flows to a scanning circuit of a control part 1a, and it is detected in the same way as if a key is depressed. However, unless a ten key board 5a is connected, this signal (a) is not transmitted to the scanning circuit. Accordingly, in accordance with whether the signal (a) is sent to a CPU or not, whether the ten key board 5a has been connected or not is decided.
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