Time:space:space PCM TDMA telephone exchange - has test units assigned to each group of switching units for testing during operation

摘要

The time-space-space PCM TDMA telephone exchange is designed to allow its essential parts to be tested as thoroughly as possible during operation. Test units (PVC) are assigned one to each group of switching units and can be connected to these units both via the spatial part of the switching network and via the part of the PCM base line leading away from the switching units. Each test unit contains a detector from the frame identification word and a transmitter to send test words over the special part of the network and an evaluator to evaluate the same coming from the special part or from the outgoing part of the PCM base line.