Circuit arrangement for powering a subscriber station

摘要

In a telephone subscriber station, virtually all the loop current is used to power the ancillary devices by providing an electronic speech circuit with return loss according to the compensation principle and a shunt component formed from a loop current sensor and a shunt controller connected in series with the latter is provided between the speech wires, the DC output signal of the loop current sensor being fed to the shunt controller. Furthermore, the shunt controller receives the AC signal of the microphone which is added to the DC signal and the shunt controller thus modulates the DC current which flows through it. The ancillary devices are powered by a power distribution circuit.