Charles J Funk

US Patent:

39379086, Feb 10, 1976

Filed:

Jan 27, 1975

Appl. No.:

5/544235

Inventors:

Charles John Funk - Columbus OH
George Minchenko - Reynoldsburg OH

Assignee:

Bell Telephone Laboratories, Incorporated - Murray Hill NJ

International Classification:

H04M 324

US Classification:

1791752R

Abstract:

A network path test circuit for testing call connections established through the switch network of a telephone toll switching office. Common control equipment of the telephone toll switching office momentarily applies a tone signal to the transmit and receive paths of a call connection prior to outpulsing a called telephone station directory number. Detector apparatus measures the impedance reflected back over the call connection to determine the absence and existence of path transpositions in the call connection. The common control equipment is enabled to establish another call connection when the reflected impedance indicates path transpositions in the call connection.