Browse Prior Art Database

Outward Dialing Control in an Electronic PBX

IP.com Disclosure Number: IPCOM000074050D
Original Publication Date: 1971-Mar-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Schiesser, H: AUTHOR

Abstract

In order to control the digit values and the interdigit times of call signals sent on a trunk by the program of an electronic PBX, it is proposed to handle those values and times as a 16-bit pattern stored into a word; each significant bit representing a pulse time. The pattern, which is updated every pulse period, represents the trunk outpulsing status at any tine (interdigit time, end of interdigit, digit currently pulsed, end of pulsing of the current digit).

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Outward Dialing Control in an Electronic PBX

In order to control the digit values and the interdigit times of call signals sent on a trunk by the program of an electronic PBX, it is proposed to handle those values and times as a 16-bit pattern stored into a word; each significant bit representing a pulse time. The pattern, which is updated every pulse period, represents the trunk outpulsing status at any tine (interdigit time, end of interdigit, digit currently pulsed, end of pulsing of the current digit).

During outgoing calls, the outward dialing control program must repeat on trunks, as soon as possible and with the appropriate frequency, all digits composing area codes and PSN numbers.

Digits received from terminals are packed sequentially into words under hexadecimal format (4 digits per word).

For a given call, once the first digit is received from the inside of the PBX, the outpulsing starts to the outside.

At that time, the current digit is unpacked under a 16-bit pattern format. The significant part of this pattern is made of 1's and is right justified in a word. The number of 1 bits represents exactly the digit value, and digit zero is given the value ten as it is shown below:

(Image Omitted)

Each time a pulse period elapses (100 ms) the pattern is shifted right one bit position in order to decrement its value by one. At the same time a bit ) enters the left part of the pattern.

When the word reaches the value zero, the pulsing of the current digit is c...