Testing system for cross-point switches in telephone exchange - sends test signals via cross-point switch under test to receiver

摘要

The testing system for a telephone exchange circuit has one cross-point switch closed in each intermediate line for the duration of the test. The test transmitter and receiver are connected to different parallel intermediate lines. The two cross-point switches in each pair of lines are not simultaneously located on an intermediate line lying perpendicular to these intermediate lines. Two not-yet-closed cross-point switches under test located in an intermediate line parallel to the first-named intermediate lines are connected to the points where these lines meet the intermediate lines perpendicular to them and containing the closed cross-point switches. The crossing points in a typical matrix are typically referenced by odd numbers are intermediate letters in a square matrix system. viz., (ZL1, ZL3, ZL5, ZL7...) and (ZLb, ZLd, SLf.....). The transmitter (S) and receiver (E) are connected to the outer pair of lines.