Importance

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Abstract

An apparatus for restricting outgoing telephone calls 10 includes field effect transistors 501, 502, 503, 504 and 505 connected to telephone lines 11 and 12 in a nonpolar configuration. Signal conditioners dual tone multifrequency integrated circuit decoder 301 and operational amplifier 302 are connected to the MPTs. The outputs of dual tone multifrequency integrated circuit decoder 301 and off amp 302 are directed to microprocessor and piggyback ROM combination 101. Microprocessor and piggyback ROM 101 analyze, store and compare subsequent dialed telephone numbers to restrict particular outgoing calls. Microprocessor and piggyback ROM combination 101 is configured to allow or disallow a particular telephone number based upon an area code, and/or the local office exchange code and/or the particular four-digit customer number. A method for programming call restricting apparatus 10 is provided and uses a permanently disconnected toll-free line which is always allowed to obtain a clear line which is free from further service attempts by the central office exchange. Microcontroller and piggyback ROM combination 101 if further configured to accept program control codes and restricted or allowed numbers from the user by accepting digits dialed from a connected telephone pad by the user.

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First Claim