Raymond Howard Simpson

US Patent:

49225154, May 1, 1990

Filed:

Jul 25, 1989

Appl. No.:

7/384952

Inventors:

Raymond A. Simpson - Marietta GA

Assignee:

American Telephone and Telegraph Company - New York NY

International Classification:

H04M 324

US Classification:

379 6

Abstract:

Cut-off malfunctions in a communication network are lcoated by establishing a connection through the network between a first terminal and a second terminal. At the first terminal, a prescribed sequence of first signals is generated and applied to the established network connection. At the second terminal, a second signal is generated responsive to receipt of a first signal over the established connection and the second signal is applied to the established network connection. A signal representing the difference between the number of first signals applied to the established connection and the number of second signals received from the established connection is formed at the first terminal. The established connection is maintained for testing when the difference signal exceeds a predetermined number.