| 摘要 |
PURPOSE:To prevent a call signal to a subordinate station from continuing, by stopping a call signal from a master station by sending an answer signal out of the subordinate station corresponding to the call signal from the master station to the subordinate station. CONSTITUTION:The master station is provided with transmitter-receiver 1 and connected to the subordinate station by radio. The subordinate station is connected to line wires via the master station and usable as an interphone. As an incoming signal arrives at the master station from the line wire, bell signal detecting circuit 15 operates, and the subordinate station calling tone signal f1 generating circuit generates signal f1. Even when the master station operates calling switch 14, call signal f1 is outputted. On receiving call signal f1, the subordinate station drives the call signal generating circuit to indicate the existence of the incoming through the speaker. When the subordinate station closes the answer switch, answer signal f2 is generated. On receiving answer signal f2, the master station operates relay RY-2 to connect the telephone set to the subordinate station, and also stops the transmission of call signal f1. |
