Method and apparatus for the detection of fraudulent toll telephone calls
First Claim
1. In a telephone system comprising an originating office, and a destination office connected to said originating office via a transmission path, said originating office comprising a toll call processing system and an automatic message accounting system including at least one automatic message accounting trunk circuit connected to said call processing system, and wherein control signalling between said offices comprises using the predetermined presence or absence of a single frequency signal on said transmission path including a proceed-to-send signal transmitted from said destination office to said originating office, a method of detecting a fraudulent toll telephone call comprising the step of detecting a supervisory signal at the automatic message accounting trunk circuit, said supervisory signal corresponding to a second proceed-to-send signal from the destination office.
0 Assignments
0 Petitions
Accused Products
Abstract
Fraudulent toll telephone calls are detected by the recognition of extraneous supervisory signals which are generated in the originating office in response to a perpetrator placing such a call. The invention provides a means of detecting a second proceed-to-send signal received at the originating office and of recording in memory means the identities of the calling and called parties. Timing means for achieving the detection is connected to the automatic message accounting trunk circuit of the originating office and, upon detection, an MF receiver is also connected thereto for a predetermined interval of time.
-
Citations
11 Claims
- 1. In a telephone system comprising an originating office, and a destination office connected to said originating office via a transmission path, said originating office comprising a toll call processing system and an automatic message accounting system including at least one automatic message accounting trunk circuit connected to said call processing system, and wherein control signalling between said offices comprises using the predetermined presence or absence of a single frequency signal on said transmission path including a proceed-to-send signal transmitted from said destination office to said originating office, a method of detecting a fraudulent toll telephone call comprising the step of detecting a supervisory signal at the automatic message accounting trunk circuit, said supervisory signal corresponding to a second proceed-to-send signal from the destination office.
-
6. In a telephone system comprising an originating office, a destination office connected to said originating station via a transmission path and wherein control signalling between said offices comprises using the predetermined presence or absence of a single frequency signal on said transmission path including a proceed-to-send signal transmitted from said destination office to said originating office, a method of detecting a fraudulent toll call comprising the step of detecting the presence of a second proceed-to-send signal at said originating office during any one call.
- 7. A telephone system comprising in combination, an originating office and a destination office connectable together via a transmission path, the originating office comprising a toll call processing system including an outgoing single frequency circuit and an automatic message accounting system including an automatic message accounting trunk circuit, the destination office comprising an incoming single frequency signalling circuit, wherein control signalling between said originating and destination offices is achieved using the predetermined presence or absence of a single frequency signal on said transmission path including a proceed-to-send signal transmitted from said destination office to said originating office, and means for detecting the presence of a second proceed-to-send signal appearing at said originating station during any one call.
Specification