| 摘要 |
PROBLEM TO BE SOLVED: To decrease the number of pins for connecting signal lines without limiting the number of keys. SOLUTION: For output signal lines for key scanning, a key scan circuit 12 which outputs signals in sequence so as to check a depressed key, a key detecting circuit 14 which specifies the depressed key according to the input from input signal lines for key detection, and switches which connect specific groups of output signal lines for key scanning and input signal lines of key detection to each other when a key is pressed and correspond to the keys are provided, and the keys correspond to the switches which connect different groups of the signal lines for key scanning and input signal lines for key detection are provided.
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