Ming Jeng Lee

US Patent:

59303450, Jul 27, 1999

Filed:

May 20, 1997

Appl. No.:

8/858940

Inventors:

Steven F. Dauble - Dumont NJ
Joseph I. Hermo - Summit NJ
Ming Ho Lee - Holmdel NJ
Astley George Nelson - Edison NJ

Assignee:

Lucent Technology Inc. - Murray Hill NJ

International Classification:

H04M 1700
H04M 166
H04M 1500

US Classification:

379145

Abstract:

To prevent so-called "clip-on" fraud from occurring at a public telephone station, such as a coin operated public telephone, a unique signature identifier is transmitted at the telephone following the transmission of the dialed number. If remote equipment determines that the expected identifier is not correct, or it fails to receive the signature, then the remote equipment terminates the call. Once the call is completed, then the public telephone is expected to periodically transmits a second identifier. The completed call may also be terminated if the remote equipment does not receive the expected second identifier at an expected rate or if a received second identifier is not correct.