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Communication Procedure Between Digital Telephone Sets and a Cluster Attachment Box

IP.com Disclosure Number: IPCOM000080972D
Original Publication Date: 1974-Mar-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Austruy, PC: AUTHOR [+3]

Abstract

Digital telephone techniques define some new concepts such as a cluster attachment box. This box acts as an interface between a high-speed, high-reliability loop and a plurality of telephone sets, which are generally low-cost devices working at a low speed and requiring no high-reliability characteristics. Where communication facilities between the box and the telephone sets use a delta code, the proposed scheme consists in transmitting bits between the box and the telephone sets at twice the speed of the delta code. Every other bit is used for speech transmission, and the other bits are used for the transmission of control information (synchronization, commands and status bits) which is therefore available at each frame.

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Communication Procedure Between Digital Telephone Sets and a Cluster Attachment Box

Digital telephone techniques define some new concepts such as a cluster attachment box. This box acts as an interface between a high-speed, high- reliability loop and a plurality of telephone sets, which are generally low-cost devices working at a low speed and requiring no high-reliability characteristics. Where communication facilities between the box and the telephone sets use a delta code, the proposed scheme consists in transmitting bits between the box and the telephone sets at twice the speed of the delta code. Every other bit is used for speech transmission, and the other bits are used for the transmission of control information (synchronization, commands and status bits) which is therefore available at each frame. The meaning of the control bits depends on their location within the frame and the direction of the transmission (box to telephone sets or vice versa).

A simple coding of commands and status may be used: one bit per command or status, which still enables multiple information to be sent simultaneously (the priority transmission queues are eliminated). Commands and status are sent continuously, thereby eliminating the need for memorizing each status in the box, and the use of status request procedures. This process enables the box to check whether a command has been executed or not, by reading the corresponding telephone set status arriving in the next frames.

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