SUBSCRIBER CONNECTING CIRCUIT FOR THE CONNECTION OF A SUBSCRIBER LINE TO THE EXCHANGE OF A DIGITAL TIME DIVISION MULTIPLEX COMMUNICATION SYSTEM

摘要

At least the part (SLIC) of the circuit comprising the indication circuit for loop state recognition is disconnected in idle mode from the feed current source (-UB) for power-saving reasons. In this case, an external indication circuit (OP) is active, which is permanently connected via a balanced resistance network (R) to the wires (a, b) of the subscriber line (TL) and whose supply voltage lies below the value of the supply voltage of the subscriber connecting circuit by an amount equal to the response voltage of a common protective circuit (SS). This has no adverse effect on the transmission characteristics of the subscriber connecting circuit and reduces the risk of a false indication through response of the protective circuit due to longitudinal voltages.