Fraud prevention in a public telephone station
First Claim
1. A fraud prevention circuit for use in a telephone station for restricting telephone calls originating at the station, the circuit comprising:
- means for establishing an initial telephone connection between the telephone station and a switching facility over a pair of input lines;
means for receiving a loop break from the switching facility, the loop break being reflective of a momentary interruption in the telephone connection;
means for receiving a dial tone signal from the switching facility; and
means for receiving a call screening process in the telephone station, the call screening process allowing only certain telephone calls to originate at the telephone station, and the means for activating the process being provided in response to the joint reception of the loop break and the dial tone signal from the switch facility.
1 Assignment
0 Petitions
Accused Products
Abstract
Control equipment employed in a customer-owned public telephone station prevents a user from making unauthorized telephone calls in the telephone system. Operating under the control of a computer in the station, the control equipment is responsive to momentary loop breaks occurring on tip and ring lines connecting the station to a central office, and to a loop break provided by the central office which reflects that the far end party has disconnected. The control equipment is also responsive to scheduled as well as as unscheduled receipt of dial tone. The combination of ongoing loop break and dial tone detection and analysis conveniently provides the desired protection for reliable operation of the customer-owned public telephone station in the telephone system. Restrictions incorporated in the station for obtaining the desired protection are applied with minimal inconvenience for the legitimate user.
27 Citations
16 Claims
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1. A fraud prevention circuit for use in a telephone station for restricting telephone calls originating at the station, the circuit comprising:
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means for establishing an initial telephone connection between the telephone station and a switching facility over a pair of input lines; means for receiving a loop break from the switching facility, the loop break being reflective of a momentary interruption in the telephone connection; means for receiving a dial tone signal from the switching facility; and means for receiving a call screening process in the telephone station, the call screening process allowing only certain telephone calls to originate at the telephone station, and the means for activating the process being provided in response to the joint reception of the loop break and the dial tone signal from the switch facility. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A fraud prevention circuit for use in a telephone station for restricting telephone calls originating at the station, the circuit comprising:
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means for establishing an initial telephone connection between the telephone station and a switching facility over a pair of input lines; means for receiving a loop break from the switching facility, the loop break being reflective of a momentary interruption in the telephone connection; means for receiving a dial tone signal from the switching facility; and means for terminating the telephone connection between the telephone station and the switching facility, the means for terminating being provided in response to the joint reception of the loop breaks and the dial tone signal from the switching facility.
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8. A method of restricting telephone calls originating from a telephone station having input lines connected to a switching facility, the method comprising the steps of:
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establishing an initial telephone connection between the telephone station and the switching facility over the input lines; receiving a loop break from the switching facility, the loop break being reflective of a momentary interruption in the telephone connection; receiving a dial tone signal from the switching facility; and activating a call screening process in the telephone station, the call screening process allowing only certain telephone calls to originate at the telephone station, and the activating step occurring in response to the joint reception of the loop break and the dial tone signal from the switching facility. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A method of restricting telephone calls originating from a telephone station having input lines connected to a switching facility, the method comprising the steps of:
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establishing an initial telephone connection between the telephone station and the switching facility over the input lines; receiving a loop break from the switching facility, the loop break being reflective of a momentary interruption in the telephone connection; receiving a dial tone signal from the switching facility; and terminating the telephone connection between the telephone station and the switching facility, the terminating step occurring in response to the joint reception of the loop break and the dial tone signal from the switching facility. - View Dependent Claims (15, 16)
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Specification