| 摘要 |
A filter component (3), which forwards the AC charge pulses to the control input (41) of a pulse transmitter (4), and a filter component (5), which forwards the AC speech current and the DC loop current to the telephone set (1), are connected to the subscriber loop (a1, b1). The pulse transmitter (4) supplies a DC counting pulse for each AC charge pulse to a counter (8). The pulse transmitter (4) is fed from a capacitor (7) which supplies the DC counting pulse power, is charged with DC loop current when the subscriber loop circuit closes and, once the loop is closed, is recharged after each DC counting pulse so that the pulse transmitter (4) also supplies a DC counting pulse when a further AC charge pulse occurs once the subscriber loop has opened. <IMAGE>
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