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Route Optimization by a PABX

IP.com Disclosure Number: IPCOM000045645D
Original Publication Date: 1983-Apr-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 14K

Publishing Venue

IBM

Related People

Austin, J: AUTHOR [+4]

Abstract

Route optimization helps reduce the cost of telephone calls outside the local calling area by allowing a Public Switched Network (PSN) call to be automatically serviced by a Private Automatic Branch Exchange (PABX) using the most economically available trunk circuit. Route optimization makes use of tables initiated through the PABX table generation procedure.

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Route Optimization by a PABX

Route optimization helps reduce the cost of telephone calls outside the local calling area by allowing a Public Switched Network (PSN) call to be automatically serviced by a Private Automatic Branch Exchange (PABX) using the most economically available trunk circuit. Route optimization makes use of tables initiated through the PABX table generation procedure.

The trunks or the tie lines attached to the system are arranged in groups of several external lines with the same characteristics and connected to the same central office. The external line groups to be used when a specific PSN number is dialed are recorded in a Route table. The Route table contains a list of entries. Each entry records a PSN number or the initial digit sequence of a PSN number. Each entry gives access to up to four different groups that can physically handle the call. For example, 10 different groups of trunks, and 25 groups of tie lines are available. The contents of the Route table can be updated by the supervisor.

Each group of external lines can have different toll rates according to the time of day. Several different toll rates can be considered for each group. Usually three daily toll rates are defined for Direct Distance Dialing (DDT) lines.

The limits of the periods of time are chosen by the customer and recorded in the Toll Rate table. Some groups can have a flat rate whatever the time of day.

The Toll Rate table records the toll rates (in cents per minute) applicable to each group of external lines according to: . the distance of the call for DDD lines or the type of the line, and . the period of time of day.

The data of the Toll Rate table is initialized according to the customer's needs, and can be updated. According to the current time of day, the system determines the corresponding toll rate for each group. The priority among the four groups is then chosen, beginning with the cheapest.

Access to the different groups is permanently controlled by the class of service of the caller. This allows access to expensive groups to be controlled, and access to insecure (privacy-wise) tie lines to be avoided, if necessary.

Each tide a PSN number is dialed, a check is performed at last digit detection. If the call is a local one, or if it is a free toll call, DDD groups are automatically selected. For the other dialed PSN numbers, a match is searched for in the Route table on a partial or whole PSN number. If no match is found, the DDD lines are used. The Route table automatically identifies the external line groups that are to serve the call. In addition, it gives the appropriate en...