PICTURE COMMUNICATION EQUIPMENT AND SIGNAL DETECTOR

PURPOSE:To prevent a caller from receiving a sense of disease or a sense of disorder in the case of an incoming call from a telephone set or a manual transmission picture communication equipment by allowing the picture communication equipment to await the arrival of a non-voice terminal identification (CNG) signal while outputting a pseudo signal of a ring back tone(RBT) to a telephone line. CONSTITUTION:When a call signal comes from a public telephone line 1 and its detection signal is outputted from an incoming call detection section 2, a control section 18 changes over a line changeover section 5 to the position of a network control section 4 to close the line and starts a pseudo RBT output section 7 to start a line output of a pseudo RBT signal and initializes a CNG detection discrimination section 13 to monitor the output of the CNG detection discrimination section 13. While the pseudo RBT signal is outputted to a telephone line, the arrival of a CNG signal is awaited and when the CNG signal is detected, the operation is switched to the operation of the picture communication automatically. Thus, in the case of the incoming call from a telephone set or a manual transmission facsimile equipment or the like, a person at the caller hears a sound similar to a ring back tone and feels no disease.