| 摘要 |
PURPOSE:To surely make restriction of transmission of a button telephone set having a holding function, by sequentially storing the dial number at telephone set side, generating a transmission restricting signal based on the stored value and inhibiting the dial call afterward. CONSTITUTION:A dial tone by off-hook is detected at a circuit 14, and detected output is applied to a dial number discriminating circuit 12. Thus, the memory in the circuit 12 is initialized and a dial transmission inhibiting circuit 13 is in inhibited opeation release state. At this state, when an input is given from a dial key pad 11, a signal is applied to a transmission circuit 2 via a circuit 13 and stored in the circuit 12. The circuit 12 discriminates if the stored value is the number to make restriction of transmission, and if to be restricted, the transmission restriction signal is transmitted to the circuit 13 to avoid dial signals afterward from being transmitted to the circuit 2. |
