US 3,940,569 AGranted

Programmable toll restrictor

AssigneeE & M Communications Corporation

InventorsLeslie B. Schonbrun, Friedrich W. Schwaar

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Abstract

A toll restrictor for use in determining whether attempts to complete a trunk call are unrestricted is responsive to at least a first successively dialed three digit code of the call from the trunk to provide a control signal in response to this code being a restricted code to prevent the completion of the call having this code. The restrictor includes a registration portion which comprises relay means responsive to the dialed digits for initially registering the first two successively dialed digits of the code as a first tens digit group and the last successively dialed digit of the code as a second ones digit group. The first tens digit group enables the provision of a family of ten three digit codes having a common first two dialed digits. The registration portion also comprises second relay means responsive to at least the first tens digit group for providing the control signal when at least the tens digit group indicates a restricted three digit code. Only a portion of the three digit codes in a family of such codes can be restricted by the interposition of a relay means, such as a reed relay means; which is operable in response to the provision of at least one unrestricted three digit code in a restricted family of such codes to prevent the operation of the second relay means when the reed relay means is operated. The toll restrictor may also include means operatively connected to the first relay means which are responsive to the first provided digit being a predetermined digit, such as a unique long distance access code, for resetting the toll restrictor to the initial state thereof in response thereto.

A toll restrictor for use in determining whether attempts to complete a trunk call are unrestricted, said toll restrictor being responsive to at least a first successively dialed three digit code of said call from said trunk and providing a control signal in response to said first dialed three digit code being a restricted code to prevent the completion of a call having said first dialed three digit code, said toll restrictor comprising a binary counting chain portion and a digit registration portion, said binary counting chain being responsive to dial pulses associated with each of said dialed digits in said code for providing a binary equivalent thereof, said dialed digits being successively individually provided to said counting chain one at a time;

said counting chain portion successively individually providing said dialed digit binary equivalents to said registration portion for registration of said dialed digits;
and said registration portion comprising a first and a second binary to decimal converter means for converting said first and second dialed digit binary equivalents to respective first and second signals corresponding to the equivalent decimal digit, said second binary to decimal converter means being further operable to convert said third dialed digit binary equivalent to a third signal corresponding to the equivalent decimal digit, first relay means responsive to said first and second signals for initially registering the first two successively dialed digits of said first dialed three digit code as a first tens digit group and responsive to said third signal for registering said last successively dialed digit of said first dialed three digit code as a second ones digit group, said first tens digit group enabling the provision of a family of ten three digit codes having a common first two dialed digits, and second relay means responsive to at least said first tens digit group for providing said control signal when at least said tens digit group indicates a restricted three digit code.

Abstract

Claims14