| 摘要 |
PURPOSE:To make an effective use of a line by discriminating a modem signal from a voice signal, demodulating only the modem signal without applying a band-compression, and converting the transmission rate to make it closest to the signal rate of modem signal. CONSTITUTION:Whether an input signal is a modem signal such as a facsimile signal, etc., or a voice signal is discriminated by a signal discrimination circuit 1, and in the case of a modem signal, the signal is demodulated by a modem signal transmission circuit 2, and the signal is transmitted to a transmission line at a transmission rate closest to its signal rate, but in the case of a voice signal, the signal is compressed with its band by a voice compression circuit 3 then transmitted to the transmission line. Therefore, a modem signal is not subjected to a band compression, hence it does not occupy the whole frequency band of a voice signal. As a result, the quality of a modem signal does not deteriorate even if the number of repeating links is increased, and a digital line can be effectively occupied.
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