| 摘要 |
PURPOSE:To control effectively telephone terminals by using a circuit for lamp driving signal transmission as a call signal sending circuit commonly and transmitting call signals or lamp driving signals to called telephone terminals. CONSTITUTION:Relay Nn for a called telephone set, for example, EXTn is operated by common control unit CC, and its contacts nn1 and nn2 are switched, and the telephone set side is connected to call signal sending circuit RT. Then, unit CC operates relay M to send telephone signals to telephone set EXTn and repeat sounding operations. Next, relay Nn for called telephone set ETn is operated by unit CC, and its contacts nn1 and nn2 are switched to the call signal sending circuit RT side, and lamp driving signals are sent to telephone set EXTn to repeat lamp flashing. As a result, call signals or lamp driving signals are sent to the called telephone terminal in a simple constitution, so that telephone terminals can be controlled effectively. |
