| 摘要 |
PURPOSE:To perform an extension speech operation via a telephone circuit by providing a telephone circuit voltage detection circuit set at a telephone circuit voltage detectable state by issuing the output of a call signal detection circuit, and closing the hook switch of a master set simultaneously with the detection of the voltage drop of a telephone circuit. CONSTITUTION:By operating the call signal generation circuit of a slave set and transmitting a generated call signal to the master set 2, the master set 2 performs the detection of the call signal at the call signal detection circuit 33, and performs a vocalizing operation with respect to the detection of the call signal via vocalizing means 29-31, and also, sets the telephone circuit voltage detection circuit 34 at an operating state, and generates the detectable state of the off-hook operation of a telephone set 37 connected to the telephone circuit. And when the off-hook of the telephone set 37 is performed corresponding to the vocalization of the vocalizing means, the voltage drop of the telephone circuit is detected by the telephone circuit voltage detection circuit 34, and the master set 2 is connected to the telephone circuit. In such a way, it is possible to perform the extension speech operation between the slave set and the telephone set 37 via the telephone circuit. |
