Telephone circuit

摘要

Telephone circuit using a transconductance switch in a high current line with the voice network, and a dial network in a low current line with the control input of the switch to provide dial input signals at the control input and send dial pulse signalling along the high current line through the voice network. The voice network includes a current clamp to stabilize the high current through the switch to the voice network sufficiently quickly to establish the desired waveform during dialling.