Abstract: In a communication network, a method and apparatus is provided to detect the presence of loopback errors over facilities interconnecting switches of the network. According to the test protocol, an originating switch generates a tone on a forward trunk associated with the facility and monitors the return trunk for the presence of that tone. If the return trunk contains the tone, the originating switch fails the facility for a loopback condition. The loopback test protocol complements conventional continuity tests and results in greater reliability of communications networks.

Abstract: A switch architecture that permits maintenance of switch signaling interfaces in switches for communication networks. The architecture provides a spare switch signaling interface that is enabled when a regular switch signaling interface is disabled. A switch matrix routes signaling channels from their dedicated position in a trunk to the spare switch signaling interface when the spare is enabled. A control processor updates a memory log associating the signaling channel and the trunks from which they originate with the spare switch signaling interface.