METHOD AND EQUIPMENT FOR PERFORMING AUTOMATIC SWITCHING BETWEEN TRANSMISSION OF SPECTRALLY REDUNDANT OUTGOING SIGNAL AND RECEPTION OF INCOMING SIGNAL

摘要

PURPOSE: To conduct automatic switching between transmission and reception in an excellent way by attenuating a component included in a spectrum of an incoming signal so as not to be included in a transmission signal in the case of communication via a partial reflectance 2-way communication channel thereby avoiding disturbance of the incoming signal due to an echo of the transmission signal. CONSTITUTION: A call (CNG) signal form a facsimile equipment 12 via a data access device 21 and an A/D converter 22 is detected by a CNG signal detector 24, a voice response machine 14 is made disable and the device 12 is made enable and the transmission/reception is automatically switched. A transmission signal via the machine 14 and a speech compander 17 is given to a notch filter 16, in which a component of a redundant CNG signal in a spectrum is attenuated. Thus, the detector 24 surely detects the CNG signal by avoiding disturbance due to an echo of the transmission signal and the automatic switching between the transmission and the reception is conducted in an excellent way.