Telephone call restricting apparatus
First Claim
1. A telephone call restricting apparatus for connection to a telephone line for preventing the completion of a toll call by a telephone device connected to the line, the apparatus comprising:
- decoder means for connection to the line, said decoder means being responsive to signals develpoed on said line as each digit of a telephone number is dialed including pre-prefix digits, prefix digits, area code digits, central office digits and local number digits and operative to generate decoded digit signals;
means for storing at least some of said decoded digit signals;
means for comparing the decoded digit signals when stored with a prestored list including information relative to whether a predetermined combination of central office digits correspond to a permissible local call, and for developing a first signal when the central office digits portion of said stored digit signals does not correspond to that of a local call;
first detector means for monitoring said stored decoded digit signals and for developing a second signal when the first digit of said stored decoded digit signals corresponds to a "0" or to a "9" followed by a "0";
second detector means for monitoring said stored decoded digit signals and for developing a third signal when the second area code digit of said stored decoded digit signals corresponds to a "0" or a "1";
third detector means for monitoring said stored decoded digit signals and for developing a fourth when the central office digits of said stored decoded digit signals correspond to the number "555";
fourth detector means for monitoring said stored decoded digit signals and for developing a fifth signal when the area code digits of said stored decoded digit signals correspond to the number "(800)";
logic means responsive to said first signal or said second signal and operative to develop a sixth signal and responsive to said third signal and operative to develop said sixth signal in the absence of said fourth signal and said fifth signal; and
means responsive to said sixth signal and operative to abort the call so as to prevent completion of a toll call.
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Accused Products
Abstract
A telephone call restricting apparatus for preventing toll calls and including circuitry for sequentially decoding the signals representing each digit of a telephone number, storing the first seven decoded digit signals in binary and converting the stored signals into decimal number signals, a comparator for comparing the decimal number signals corresponding to the appropriate digits of the telephone number with permissable local central exchange digits stored in a programmed memory device, a 90 detector and 0/1 detector for detecting long distance calls, an 800 detector and a 555 detector for detecting toll free long distance calls and logic responsive to both the comparator and the detectors and operative to abort unapproved toll calls.
61 Citations
8 Claims
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1. A telephone call restricting apparatus for connection to a telephone line for preventing the completion of a toll call by a telephone device connected to the line, the apparatus comprising:
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decoder means for connection to the line, said decoder means being responsive to signals develpoed on said line as each digit of a telephone number is dialed including pre-prefix digits, prefix digits, area code digits, central office digits and local number digits and operative to generate decoded digit signals; means for storing at least some of said decoded digit signals; means for comparing the decoded digit signals when stored with a prestored list including information relative to whether a predetermined combination of central office digits correspond to a permissible local call, and for developing a first signal when the central office digits portion of said stored digit signals does not correspond to that of a local call; first detector means for monitoring said stored decoded digit signals and for developing a second signal when the first digit of said stored decoded digit signals corresponds to a "0" or to a "9" followed by a "0"; second detector means for monitoring said stored decoded digit signals and for developing a third signal when the second area code digit of said stored decoded digit signals corresponds to a "0" or a "1"; third detector means for monitoring said stored decoded digit signals and for developing a fourth when the central office digits of said stored decoded digit signals correspond to the number "555"; fourth detector means for monitoring said stored decoded digit signals and for developing a fifth signal when the area code digits of said stored decoded digit signals correspond to the number "(800)"; logic means responsive to said first signal or said second signal and operative to develop a sixth signal and responsive to said third signal and operative to develop said sixth signal in the absence of said fourth signal and said fifth signal; and means responsive to said sixth signal and operative to abort the call so as to prevent completion of a toll call. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification