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

Kenneth D Frantzen

Richard L Else

A system and method are disclosed for automatically disabling call communications through a switching system until answer supervision is received for the call. A four-wire switching system includes a fraud control unit which disables communications over the established transmit portion of a four-wire call connection through the switching system and prevents normal communications from a calling to a called line. However, normal call progress signals are allowed to pass on the established receive portion of the call connection from the called to the calling line. The fraud control unit includes a generator for generating idle code and a selector for inserting either the idle code from the generator or caller communications on the transmit portion of the call connection from the calling to the called line. The selector is controlled by a selector control unit under the control of the central processor of the switching system. When answer supervision is received for the call, the central processor causes the fraud control unit to remove the disabling of communications on the transmit path so that normal communication may proceed from the calling to the called line.

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Winfield, IL, United States of America

Kenneth D Frantzen