| 摘要 |
In a telecommunications network, testing of pre-ringing signalling at customer's premises (3), for example, signalling to activate a caller display unit (15), may be effected remotely. By establishing a test call through the network by way of a dial-back loop (8) to a test telephone number (11), establishing a second call through the network to the required telephone (6) and simulating pre-termination conditions at network termination (14), actual signalling tones at the network edge are monitored by corresponding apparatus (16) to that present at customer premises (3). |
