Browse Prior Art Database

Variable Rate Communication Link

IP.com Disclosure Number: IPCOM000088015D
Original Publication Date: 1977-Apr-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Callahan, RW: AUTHOR [+2]

Abstract

A communication adapter is described which enables data processors and peripheral devices to select the optimum data rate in terms of cost for the particular processor or peripheral device in use at the moment. The communication link is a fiber-optic transmission line, either serial or parallel. Light-emitting diodes are switched on and off to transmit data, and photodetector diodes are used to receive the data. The link is a master/slave relationship where only the master has a poll table listing the optimum data rates for the different slaves. The links to the slaves are point to point.

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Variable Rate Communication Link

A communication adapter is described which enables data processors and peripheral devices to select the optimum data rate in terms of cost for the particular processor or peripheral device in use at the moment. The communication link is a fiber-optic transmission line, either serial or parallel. Light-emitting diodes are switched on and off to transmit data, and photodetector diodes are used to receive the data. The link is a master/slave relationship where only the master has a poll table listing the optimum data rates for the different slaves. The links to the slaves are point to point.

Experience has shown that communications links operating at very high data rates, for example, 64 megabits per second, are too costly for use with many types of peripheral devices. This is especially true for remote printing applications that use relatively slow and low-cost printers.

With reference to Fig. 1, the novel communication link described herein includes a point-to-point fiber-optic link using light-emitting diodes to transmit and silicon photodiodes to receive the data. The master station contains all the point- to-point links, and the master oscillator output is subdivided to match the different data rates that may be required.

The poll table, one entry of which is shown in Fig. 2, is available only to the master station, and contains a code value which indicates the rate at which the slave is capable of communicating efficiently. The...