| 摘要 |
PURPOSE:To select other handset optionally by setting call signals of different frequencies to each handset. CONSTITUTION:Call signals of different frequencies are set to each handset 1 and a selection switch 43 selecting a handset 1 desired to be called is provided on the front face of the handset 1 and the selection switch 43 is made of a slide switch. Further, a call signal generator 23 consists of oscillator circuits 23a-23c generating, e.g., signals of 1kHz, 3kHz and 5kHz, any of the oscillation circuits 23a-23c is connected to a transmission circuit 14 by the switching of switches SW1-SW3 of the selector switch 43 to generate a call signal corresponding to each handset 1. A call signal detection circuit 24 detects all the call signals coresponding to each handset 1 and the call tone generating circuit 24 discriminates whether or not the output of the call signal detection circuit 24 is coincident with the frequency of the call signal set to itself. |
