| 摘要 |
PURPOSE:To simplify a circuit constitution and control operation by inserting a signal conversion means among a data information system, a voice information system and a telephone line so as to select switchingly the transmission/reception of data information and voice information. CONSTITUTION:A 2/4-wire conversion circuit 115 is inserted among the data information system comprised of a MODEM 315 and a CPU 313, the voice information system comprised of an amplifier circuit 121, a speaker 117 and a microphone 119 and a telephone line. Then a 4-signal line circuit of the transmission/reception mode of the data and voice information is converted properly into a 2-signal circuit of a telephone line. Thus, the circuit constitution and control operation are simplified.
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