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Telephone subscriber circuit with three point dialling device - having electronic pulse generator to drive transistor forming pulsing contacts
Telephone subscriber circuit with three point dialling device - having electronic pulse generator to drive transistor forming pulsing contacts
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机译:具有三点拨号设备的电话用户电路-具有电子脉冲发生器以驱动形成脉冲触点的晶体管
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摘要
The telephone subscriber circuit is designed not only to accommodate normal dialling devices but also those that employ abbreviated or shortened numbers for dialling subscribers who are, e.g. frequently wanted, and that permit repeated dialling at the press of a button. The circuit contains a dialling device with only three connection points. A transistor forms the pulsing contacts driven by the device's electronic pulse generator. This transistor (T1) is shunted out and its base circuit open-circuited while a conversation is taking place. The shunting-out is accomplished by contacts (nsa2). The transistor is controlled via a log circuit.
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