| 摘要 |
PURPOSE:To call a person in a remote place from a public telephone with the charge for a telephone call of one coin by calling the first telephone once and calling another telephone again from the second telephone through the first telephone. CONSTITUTION:The call signal inputted from a telephone line A is applied to an incoming detecting circuit 1 and is detected to turn on switches SW1 and SW2, and a DC circuit of telephone lines A and B is closed through load circuits 3 and 4, and simultaneously, telephone line A and B are connected to a bidirectional amplifier 5 through capacitors C1 and C2. The dial tone inputted from the telephone line B is transmitted to the telephone set which calls the telephone line A; and when a push button dial signal is transmitted from this telephone set, the push button dial signal is amplified through the bidirectional amplifier and is outputted to the telephone line B. The telephone line B is connected to another objective telephone line in accordance with the push button dial signal. When the telephone line B and the objective telephone line C are connected, a telephone line C and the telephone line are connected through the bidirectional amplifier by an AC signal, and conversation or the like is possible. |
