Abstract: Transmission channels indicated as occupied in a communications system having peripheral modules are inspected for preparing subscriber-side transmission channels. A test sequence transmitter on the system side transmits a test sequence to a control unit for a selected peripheral module. The test sequence is transmitted to a test sequence receiver over a transmission channel, which is indicated as occupied and which is assigned to the peripheral module. The test sequence, which is transmitted by the test sequence transmitter, and the test sequence, which is received by the test sequence receiver, are inspected for an evaluation of conformity. In the instance of non-conformity, the selected transmission channel is disconnected in a targeted manner.

Abstract: The invention relates to a method for inspecting transmission channels indicated as occupied in a communications system having peripheral modules for preparing subscriber-side transmission channels. According to the method, a test sequence transmitter (TxTS) carries out a system-side transmission of a test sequence (TS) to a control unit (CU1) for a selected peripheral module (PM 1). The test sequence (TS) is transmitted to a test sequence receiver (RxTS) over a transmission channel (PM1_CH1), which is indicated as occupied and which is assigned to the peripheral module (PM1). The test sequence (TS_T), which is transmitted by the test sequence transmitter (TxTS), and the test sequence (TS_R), which is received by the test sequence receiver (RxTS), are inspected for an evaluation of conformity. In the instance of non-conformity, the selected transmission channel (PM1_CH1 ) is disconnected in a targeted manner.

Abstract: In communication systems, a dc voltage source can be connected via a first and a second winding of an input transformer and a subscriber line to every communication terminal equipment device by using an electronic switch. In case of an overload, the turn-off duration, i.e. the time until the disconnect of the dc voltage source is influenced dependent on a load-generated loop current by using an integrating element and a comparator. As a result thereof, short turn-off durations and, consequently, significantly reduced thermal loads on the electronic switch occur given substantial overloads. The present invention allows the use of electronic switches having a lower maximum load.