Subscriber loop tester for telephone switching systems.

摘要

A subscriber loop tester for testing local loops of telephone switching networks has a partitioned "U" interface and an internal bus architecture for converting various transceiver circuit output data formats to a common data format. The "U" interface has a high impedance transformer meeting bandwidth and line matching requirements for different line codes and protocols for ISDN telecommunication systems. The transformer is selectively coupled to option cards each containing circuitry having AC and DC terminations matching specific line codes and protocols for ISDN telecommunications systems and other types of telecommunications systems. The option cards further contain programmable attenuators for producing a proper nominal signal level as a function of the specific line code and protocol and providing variable insertion loss. A high speed bus is selectively coupled to the option cards for coupling the formatted transceiver circuit output data between the cards and a digital bus translator. The digital bus translator selectively configures the high speed bus for the transceiver output data format of the selected option card and converts the formatted output data received on the high speed bus to a common data format. Multiple source and destination audio paths in the subscriber loop tester are controlled by an audio switching matrix. <IMAGE>