American Telephone & Telegraph Co., At&t Bell Laboratories

Gerald H Thomas

Albert Joseph Sawyer

Mahmood Ahmad

Wayne L Schreiner

A distributed control switching system where the system control units cooperatively perform the terminating port determination function. The control unit associated with the terminating port stores sequence call data defining whether calls are to be completed to that terminating port or are to be forwarded to another directory number. Upon determining that a given call is a sequence call, the control unit associated with the original terminating port determines the terminating port defined by the second directory number and effects a reduction of the sequence call to a simple call between the originating port and the second terminating port. This is done either by transmitting a control message defining the originating and terminating ports to the control unit associated with the second terminating port or by returning the setup sequence to the control unit associated with the originating port which then frees any switching system resources previously allocated to the call and transmits the control message. In either case, the control unit associated with the second terminating port completes the call without knowing whether the call is a sequence call or a simple call completed to the original terminating port.

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Woodridge, IL, United States of America

Gerald H Thomas