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Subscriber telephone line loop state verification - uses detector with resistance wire coils between lines to prevent short circuit
Subscriber telephone line loop state verification - uses detector with resistance wire coils between lines to prevent short circuit
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机译:用户电话线路环路状态验证-使用检测器,线路之间带有电阻线圈,以防止短路
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摘要
The loop state of a subscriber telephone line is verified using coils connected between the lines and detector circuit. The use of series resistors for short circuit protection is eliminated by coils using resistance wire. A telephone line is connected (1, 2) to a subscriber line equipment and conductors (5, 6) permit connection to a switching circuit (4) via capacitors (7, 8). Coils (12, 14) of resistance wire connect a battery (10) to the conductor circuit whose loop state is sensed by a detector (20) also connected to the switching circuit. A third coil (22) with diode limiter (28) is coupled to the coils to enable tone signals to be sent to the subscriber. A fourth winding (24) in a wheatstone bridge (26) series temperature.
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