Method for testing the line connection before switching-over from a telephone exchange which is to be disabled, to a new digital exchange ready to be put into operation.

摘要

From the new exchange (NV), the subscriber lines are successively selected, the subscriber lines being simultaneously connected to the new exchange (NV) and to the old exchange (AV) via the main distribution frame (HV), and connections are established from a test access (T) to these subscriber lines through the old exchange. Via these connections, the audio frequency generator of the new exchange supplies a test code word which passes via a line-individual test connection contact (x) and an external test bus (EB) to the code signal receiver (CR) of the new exchange and is checked there for correspondence with the test code word. ……