Browse Prior Art Database

Four Wire Switching

IP.com Disclosure Number: IPCOM000082811D
Original Publication Date: 1975-Feb-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Boisseu, M: AUTHOR [+3]

Abstract

In order to build a network comprising a plurality of private branch exchanges linked by tie lines which are generally four-wire lines, it is necessary to provide interfaces allowing a four-wire line to be switched either on a four-wire or on a two-wire basis, depending upon the type of call to be handled.

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Four Wire Switching

In order to build a network comprising a plurality of private branch exchanges linked by tie lines which are generally four-wire lines, it is necessary to provide interfaces allowing a four-wire line to be switched either on a four-wire or on a two-wire basis, depending upon the type of call to be handled.

Each four-wire line is associated with an interface comprising a high-traffic inlet A and a low-traffic inlet B.

Inlet A comprises a four-wire converter. As long the four-wire line is switched on a two-wire basis, the high-traffic inlet is both ways. As soon as the four-wire line must be switched on a four-wire basis, the high-traffic inlet is either an incoming one-way attachment or an outgoing one.

Inlet B is an associated attachment which is unused so long as the four-wire line is switched on a two-wire basis. As soon as it must be switched on a four- wire basis, inlet B is either an outgoing one-way attachment or an incoming one.

The principle of the four-wire switching operation performed in a transit exchange, involved in a communication between two subscribers served by two different exchanges of the network, is shown in the drawing. The caller line I is associated to an incoming high-traffic inlet AI and an outgoing low-traffic inlet BI. The called line II is associated to an outgoing high-traffic inlet AII and an incoming low-traffic inlet BII.

As soon as the numbering has been received from the calling party via the REG logic and r...