Browse Prior Art Database

Duplex Synchronous Message Switching System

IP.com Disclosure Number: IPCOM000090128D
Original Publication Date: 1969-Feb-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Lebizay, MG: AUTHOR

Abstract

In a duplex system using two communication controllers working in parallel, each one receives and transmits the same data from and on the same lines and updates its particular file. When a communication controller fails, the other continues to work as if nothing happened. To effect this, the transmission is synchronized on the same adapter from the two communication controllers. This synchronization is performed by the device shown in the drawing. When communication controller A is ready, it sends a signal Set Ready A and the address of the transmission line to be accessed to latch L1 which is thus set. The set signal from L1 energizes an input of And 1 and the address from A energizes an input of And 2. When communication controller B is ready, it sets latch L2 and the set signal from L2 opens And 2.

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Duplex Synchronous Message Switching System

In a duplex system using two communication controllers working in parallel, each one receives and transmits the same data from and on the same lines and updates its particular file. When a communication controller fails, the other continues to work as if nothing happened. To effect this, the transmission is synchronized on the same adapter from the two communication controllers. This synchronization is performed by the device shown in the drawing. When communication controller A is ready, it sends a signal Set Ready A and the address of the transmission line to be accessed to latch L1 which is thus set. The set signal from L1 energizes an input of And 1 and the address from A energizes an input of And 2. When communication controller B is ready, it sets latch L2 and the set signal from L2 opens And 2. A signal B Ready is sent to A and permits transmission of data on the line during the next scanning of this line. Thus, the nonsynchronization time is shorter than the time between two scannings of the transmission line to be accessed. If communication controller B is ready first, the data is transmitted from it after a signal A Ready is sent from And 1.

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