Call screening in a public telephone station
First Claim
1. A circuit for use in a telephone station for restricting selected telephone calls originating at the station, the station having a pair of lines for connecting to a switching facility and establishing a telephone connection, the circuit comprising:
- a plurality of memory means for containing data reflective of telephone numbers categorized in distinct groupings, the plurality of memory means including;
a first memory means for containing data reflective of a group of telephone numbers to which no calls may be made;
a second memory means for containing data reflective of a group of telephone numbers to which free calls may be made;
a third memory means for containing data reflective of a group of telephone numbers to which charge calls may be made; and
the circuit further comprising comparison means for comparing each digit of a telephone number entered at the station with data reflective of a digit having a positional correspondence respectively within each memory means to the entered digit, a favorable comparison of the entered digit and the data in the first memory means preventing the completion of a telephone call, a favorable comparison of the entered digit and the data in the second and third memory means enabling the entered digit to be transmitted by the station over the pair of lines to the switching facility.
2 Assignments
0 Petitions
Accused Products
Abstract
Control equipment employed in a customer-owned public telephone station prevents a user from making unauthorized telephone calls in a telephone system. Operating under the control of a computer in the station, the control equipment employs a call screening process which restricts the telephone numbers a user can dial to those numbers preselected by a station owner. The telephone numbers are categorized in multiple but distinct groups, each of which represents a specific class of telephone call. 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 unscheduled receipt of dial tone. The combination of the call screening process along with the ongoing loop break and dial tone detection and analysis conveniently provides the desired protection so that the user will be properly charged for telephone calls made from the station. The restrictions incorporated in the station for obtaining this protection are applied with minimal inconvenience for the legitimate user.
64 Citations
12 Claims
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1. A circuit for use in a telephone station for restricting selected telephone calls originating at the station, the station having a pair of lines for connecting to a switching facility and establishing a telephone connection, the circuit comprising:
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a plurality of memory means for containing data reflective of telephone numbers categorized in distinct groupings, the plurality of memory means including; a first memory means for containing data reflective of a group of telephone numbers to which no calls may be made; a second memory means for containing data reflective of a group of telephone numbers to which free calls may be made; a third memory means for containing data reflective of a group of telephone numbers to which charge calls may be made; and the circuit further comprising comparison means for comparing each digit of a telephone number entered at the station with data reflective of a digit having a positional correspondence respectively within each memory means to the entered digit, a favorable comparison of the entered digit and the data in the first memory means preventing the completion of a telephone call, a favorable comparison of the entered digit and the data in the second and third memory means enabling the entered digit to be transmitted by the station over the pair of lines to the switching facility. - View Dependent Claims (2, 3, 4)
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5. A method of restricting selected telephone calls originating at a telephone station, the station having a pair of lines for connecting to a switching facility and establishing a telephone connection, the method comprising the step of:
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entering into a plurality of memories data reflective of telephone numbers categorized in distinct groupings, the plurality of memories including; a first memory containing data reflective of a group of telephone numbers to which no calls may be made; a second memory containing data reflective of a group of telephone numbers to which free calls may be made; a third memory containing data reflective of a group of telephone numbers to which charge calls may be made; the method further comprising the steps of; comparing each digit of a telephone number entered at the station with data reflective of a digit having a positional correspondence repectively within each memory to the entered digit; providing a signal in the station in response to a favorable comparison of the entered digit and the data in the first memory for preventing the completion of a telephone call; and transmitting the entered digit by the station over the pair of lines to the switching facility in response to a favorable comparison of the entered digit and the data in the second and third memory. - View Dependent Claims (6, 7, 8, 9, 10)
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11. A circuit for use in a telephone station for restricting selected telephone calls originating at the station, the station having a pair of lines for connecting to a switching facility and establishing a telephone connection, the circuit comprising:
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a plurality of memory means for containing data reflective of telephone numbers categorized in distinct groupings, the plurality of memory means including; a first memory means for containing data reflective of a group of telephone numbers to which no calls may be made; a second memory means for containing data reflective of a group of telephone numbers to which calls may be made; the circuit further comprising comparison means for comparing each digit of a telephone number entered at the station with data reflective of a digit having a positional correspondence respectively within each memory means to the entered digit, a favorable comparison of the entered digit and the data in the first memory means preventing the completion of a telephone call, a favorable comparison of the entered digit and the data in the second memory means enabling the entered digit to be transmitted by the station over the pair of lines to the switching facility.
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12. A method of restricting selected telephone calls originating at a telephone station, the station having a pair of lines for connecting to a switching facility and establishing a telephone connection, the method comprising the step of:
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entering into a plurality of memories data reflective of telephone numbers categorized in distinct groupings, the plurality of memories including; a first memory containing data reflective of a group of telephone numbers to which no calls may be made; a second memory containing data reflective of a group of telephone numbers to which calls may be made; the method further comprising the steps of; comparing each digit of a telephone number entered at the station with data reflective of a digit having a positional correspondence respectively within each memory to the entered digit; providing a signal in the station in response to a favorable comparison of the entered digit and the data in the first memory for preventing the completion of a telephone call; and transmitting the entered digit by the station over the pair of lines to the switching facility in response to a favorable comparison of the entered digit and the data in the second memory.
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Specification