Individual line and integrated subscriber junctor test device - has loop state simulator and multiplexer affording different voltages for digital processing

摘要

The subscriber line is connected to the line access terminals of the junctor via the loop state simulator, in which a rectifier bridge is connected to parallel switched current sources. The line and the four-wire transmission and reception terminals of the junctor are connected to a measurement system incorporating a multiplexer, which affords access also to line current terminals of the junctor and to a circuit for measuring the line capacitance between the line access terminals. The various voltage levels taken from the access terminals for the different tests on the line and junctor are all available at a common output of the multiplexer connected to a 20:1 voltage divider followed by a separate digital processing circuit.