TIDSMULTIPLEXKOPPLINGSSYSTEM MED UTRUSTNING FOER TESTNING AV LEDIG TIDSLUCKEVAEG

摘要

A time division, digital switching system capable of performing on-line testing of the actual communications paths that are switched is disclosed. When an idle network time slot is found, a test vector register places a stimulus in the idle time slot and the stimulus is directed to the address of an idle port. A loop-around path which includes a signature analysis chip (SAC) device is activated to divert a portion of the stimulus toward the SAC device. The response of the SAC device is gated to a maintenance circuit which reads the generated signature. Advantageously, the stimulus is selected to generate minimum noise at the addressed port so that if the user at the idle port picks up the telephone during the time slot used for testing, no loud noise will be heard.