7. The voice of the caller cannot be heard (incoming call).
NG Can the base and handset be connected? OK Apply the 1 kHz - 14 dBm sine waveform to the base TEL-line output. Can the 1 kHz sine waveform from Pin 4 and Pin 6 of T1 be fed? OK Check whether there is a 1 kHz sine waveform at Pin 12 of IC3. OK Can the 1 kHz sine waveform from Pin 17 of IC601 on the handset be fed?. OK Check SP931, W931, W932 and their peripheral circuit. NG Check IC601 and its peripheral circuit. NG Check IC3 and its peripheral circuit. NG Check the base TEL-line circuit and RELAY control circuit. See 3. The base and handset cannot be connected.
