Testing of ISDN line via auxiliary channel signaling

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