Jerome Joseph Zelenski

44930739, Jan 8, 1985

Aug 30, 1982

6/413156

Ronald K. Witmore - Lafayette CO
Jerome J. Zelenski - Broomfield CO

AT&T Bell Laboratories - Murray Hill NJ

H04J 314

370 14

A time division, digital switching system capable of performing on-line testing of the actual communications paths that are switched is disclosed. When an idle network time slot is found, a test vector register places a stimulus in the idle time slot and the stimulus is directed to the address of an idle port. A loop-around path which includes a signature analysis chip (SAC) device is activated to divert a portion of the stimulus toward the SAC device. The response of the SAC device is gated to a maintenance circuit which reads the generated signature. Advantageously, the stimulus is selected to generate minimum noise at the addressed port so that if the user at the idle port picks up the telephone during the time slot used for testing, no loud noise will be heard.

55219039, May 28, 1996

Dec 27, 1993

8/173903

Michael J. English - Aurora CO
Michel L. Hearn - Broomfield CO
David M. Kissel - Boulder CO
Douglas A. Spencer - Boulder CO
Jeffrey A. Williams - Thornton CO
Jerome J. Zelenski - Broomfield CO

AT&T Corp. - Murray Hill NJ

H04M 322

370 14

A port system interfaces digital PBX's to any transmission facility having DSX-1 communications ports via a microprocessor controlled PBX port board connected between PBX switch fabric and a first DSX-1 communications port. A channel service unit (CSU) module coupled directly to the port board for communications with DS1 transmission lines defines a second DSX-1 communications port which is coupled to the first DSX-1 communications port. The CSU module also includes a T1 transceiver and line interface circuitry for coupling the CSU module to a DS1 transmission line. The combination of the port board and CSU module provide full functionality of conventional CSU's while the port board alone permits direct coupling of transmission facilities utilizing a DSX-1 communications port. For remote maintenance, a microprocessor of the port board is coupled to a control processor of a PBX for control of the port board microprocessor via the PBX control processor. Wiring test circuitry is provided in the CSU module to detect faults in the wiring between a CSU module and a DS1 transmission line.