| 摘要 |
PURPOSE:To shorten communication time in terms of standard facsimile communications by attaining a call over the phone even during a start protocol executed after and before the exchange of facsimile picture information and simultaneously advancing the start protocol for facsimile communications during a call. CONSTITUTION:While a facsimile control signal is being exchanged, relays RC1 and RC2 are connected to the side of a contact point (b). After a band-pass filter BPF 3 takes out only the prescribed band(about 1750Hz) of the facsimile control signal modulated into 300 baud in a MODEM 4, said band is transmitted to a mixing part 3. If a transmission side places a call over the phone during sequence start and end protocols, a band removal filter BEF 1 removes the signal about at 1750Hz among sound signals, and the mixing part 3 synthesizes it with the facsimile control signal. The synthesized signal is transmitted to a telephone line N through a relay 6, a hybrid circuit 2 and the relay RC1. Thus a sound and the facsimile control signal can simultaneously be transmitted, and the total communication time is shortened.
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