| 摘要 |
PURPOSE:To identify the communication speed of a communication opposite equipment automatically and to set the equipment to a communication speed coincident therewith by providing 1st and 2nd modulator-demodulator section with different communication speed and a control section receiving a demodulation output signal of the 1st modulator-demodulator section and controlling the 1st and 2nd modulator-demodulator sections. CONSTITUTION:The 1st modulator-demodulator section 2 applies the modulation and demodulation of the CCITT recommendations V.22 1200bps mode, The 2nd modulator- demodulator section 3 applies modulator-demodulator of the CCITT recommendations V.21 300bps mode. A control section 1 supervises a demodulation output of the 1st modulation-demodulation section 2 for a prescribed time only and in detecting a hand- shake pattern from the communication opposite equipment from the demodulated output, the 1st modulation-demodulation section 2 is brought successivly into the operating state. In detecting no hand-shake pattern, the 2nd modulator-demodulator section 3 is operated in place of the 1st modulator-demodulator section 2 at that point of time. Thus, the communication speed of the communication opposite equipment is identified automatically and the data is communicated at a communication speed coincident therewith.
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