Browse Prior Art Database

Data Transmission System

IP.com Disclosure Number: IPCOM000094582D
Original Publication Date: 1965-Mar-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Sims, DE: AUTHOR [+2]

Abstract

Data is transmitted from one free-running asynchronous machine to another. Provision is made to insure that no data is lost due to variations in the relative speeds of the machines.

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Data Transmission System

Data is transmitted from one free-running asynchronous machine to another. Provision is made to insure that no data is lost due to variations in the relative speeds of the machines.

Data is sent according to the bit format shown in the lower drawing from magnetic tape unit 1 to magnetic tape unit 2. Unit 1 has two registers A and B, step control 3, register control 4, serializer 5, and subset 6. Unit 2 has registers C and D, step control 7, register control 8, deserializer 9, and subset 10. Subsets 6 and 10 are connected by communication lines 11 and 12. If a nominal operating speed of twenty characters per second is assumed, variations due to low line voltage, friction, and other factors can result in a speed range of plus or minus one character per second or 19 to 21 characters per second.

In an asynchronous system, if unit 1 is transmitting at twenty characters per second and tape unit 2 is operating at only nineteen characters per second, it is possible to lose one character each second. In order to compensate for the worst case condition, the system is set up for an operating rate of nineteen characters per second. Registers A and B hold the characters alternately from tape unit 1. Registers C and D receive characters alternately from deserializer 9. Step controls 3 and 7 insure proper transmission rates in the system.

Assuming the system is predicated on nineteen characters per second, if unit 1 should exceed this rate and run at tw...