| 摘要 |
PURPOSE:To enable the reception of ringer signal even if the operation of a changeover switch is in error, by providing a changeover switch of a 4-wire/2-wire type channel in a hybrid circuit of a ringer suppression circuit inserted in a two-wire channel. CONSTITUTION:A ringer suppression circuit RGR and a ringer reception circuit RRV and are inserted to a two-wire type channel 2W in common use with a four wire type channel reception side 4WR OUT, and changeover switches S1, S2 are provided at a hydrid side HYB of the circuit RRV. In case of 4-wire communication, a signal inputted to a carrier device dose not pass through the circuit RGR and passes through it only with the output from the carrier device. In case of two-wire communication, even if the operation of switches S1, S2, S5, S6 is forgotton, the ringer signal is suppressed with the circuit RGR and does not reach a variable attenuator AV2. |
