| 摘要 |
A portable ISDN test set is configured to be interfaced with any location of an ISDN link, and is operative to test the link, irrespective of the hardware configuration of the circuit, (e.g., two-wire vs. four-wire). The ISDN test set contains a digital communications controller and associated digital signalling interface circuits, including both 'U' interface and 'S/T' interfaces. The ISDN test set and a remote device, such as another test set, exchange digital communication messages over an auxiliary ISDN channel, such as an embedded operations channel or a Q channel, that are effective to cause the device to provide a loopback path over at least one ISDN bearer channel to the test set and test a prescribed operational characteristic of the link.
|
