Abstract: A method and system for automatically testing E911 systems using digital loop carrier trunks in a laboratory. A testbed running a testing program evaluates the functionality of a digital loop carrier trunk, a channel unit pair, and an E911 switch by measuring a delay and duration of an acknowledgement pulse from the E911 switch in response to an off-hook condition at a simulated PBX. The testbed and testing program also evaluate the functionality of the E911 switch and a simulated PSAP by measuring a delay and duration of a ring signal from the E911 switch in response to an emergency signal sent by the simulated PBX. Once connection between the simulated PBX and the simulated PSAP has been established, the end-to-end signal loss is also measured.

Abstract: The present invention provides a method for conveying information over a communication network such as a Digital Loop Carrier (DLC) network free of in-band signaling information for at least a portion of an established communication between at least two users so as to reduce the information error rate associated with the established communication. For communication links that support robbed-bit signaling (RBS), the RBS signaling is disabled to allow the communication link to be operated in a clear channel mode. When appropriate, operations can be switch from the clear channel mode back to the RBS mode. Embodiments are described for one-stage DLC systems having a local digital switch (LDS) connected to a remote terminal (RT) by a communication link conforming to either the TR-303 protocol or the TR-008 protocol. In addition, embodiments are described for two-stage DLC systems that also have a distance terminal (DT) connected to the RT by a second communication link.

Abstract: The present invention provides a method for conveying information over a communication network such as a Digital Loop Carrier network free of in-band signaling information for at least a portion of an established communication between at least two users so as to reduce the information error rate associated with the established communication.

Abstract: A method for reducing signal degradation in a Digital Loop Carrier System by removing signaling information normally embedded continuously in digital information being conveyed over the system. The system remains in this signaling free communication mode until it detects a change in its supervisory condition requiring that it exit from the signaling free communication mode or terminate communication allowing the system to enter an idle mode.

Abstract: Disclosed is a circuit included in a channel unit for testing that channel unit in a telecommunications system. A digital signal processor detects and reproduces signals from a local digital switch and controls a number of relays which result in various terminations appearing on the channel unit. The processor then monitors the signal levels as well as the signaling bits from the channel unit to test for proper performance.