Systems for and methods for PBX toll restriction
AssigneeStromberg-Carlson Corporation
InventorOtto Altenburger
Life of this patent
Estimating the term…
Abstract
Centralized toll restriction for private branch exchanges (PBXs) is performed by providing first and second memory addresses in the number translator of a central office switching system. The first and second addresses are matched with restricted telephone calls and unrestricted telephone calls, respectively. Those telephone lines of each PBX which are to be restricted are marked in a convenient manner, such as with tip to ground marking, while those telephone lines not restricted are left unmarked. Outgoing trunks between the PBXs and the central office switching system are temporarily marked with an unbalance upon going off-hook on a restricted telephone line, in order to transmit restriction indication to the central office switching system.
Claims6
A toll restriction system for use with private branch exchanges connected to a central office switching system, said toll restriction system comprising:
- a group of telephone lines connected through each of said private branch exchanges;
- means for marking selectively individual telephone lines within each group of telephones, wherein said marking distinguishes toll restricted telephone lines from unrestricted telephone lines;
- trunk means for connecting each private branch exchange to said central office;
- means, arranged to be energized, for marking said trunk means upon connecting a marked line to said trunk means via a said private branch exchange;
- means within said central office switching system for distinguishing between marked and unmarked trunk means and, therefore, between restricted and unrestricted telephone lines;
- means for intercepting calls made via restricted telephone lines before said restricted telephone lines are connected to a called destination;
- and
- means for transmitting unrestricted calls to called destinations.
A method of restricting service available to selected telephone lines which are connected through a private branch exchange that is connected to a central office switching system, said method comprising the steps of:
- marking those telephone lines which are restricted;
- marking an outgoing trunk connecting the private branch exchange to the central office switching system with an unbalance upon attempting to connect a call via a restricted telephone line;
- detecting the unbalance in the central office;
- and
- restricting in the central office switching system the service available to the restricted telephone line.
Dependencies are inferred from the claim text.