| 摘要 |
PROBLEM TO BE SOLVED: To allow an information terminal provided with a single phone jack of four poles or less to be connected to and used for various external connection devices in common on market for mobile phones. SOLUTION: The single phone jack of four poles or less is placed on the information terminal, and switches comprising MOS FETs 5 to 10 are provided to circuits for a transmission voice signal, a received voice signal, and a ground circuit in the information terminal connected to the phone jack, key operation of the information terminal allow the information terminal to recognize devices connected externally, the MOS FETs 5 to 10 conduct switching and revise the internal connections of the phone jack so as to allow the information terminal to cope with functions of the externally connected devices. COPYRIGHT: (C)2003,JPO
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