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Browse Prior Art Database

Data Transmission Checking by Address Prediction

IP.com Disclosure Number: IPCOM000094802D
Original Publication Date: 1965-Jun-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Adler, JG: AUTHOR

Abstract

A longitudinal redundancy check, or character count, is provided in a data processing system by eliminating a trigger at the transmitting, or CPU end of a communication link, and by using address comparison instead.

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Data Transmission Checking by Address Prediction

A longitudinal redundancy check, or character count, is provided in a data processing system by eliminating a trigger at the transmitting, or CPU end of a communication link, and by using address comparison instead.

In the drawing, a pair of And's 1 and 2 determines that an even number of characters has been received at the transmitter. This is indicated by the zero side of trigger 3 which is controlled by a Data Strobe. And's 1 and 2 also determine that an even starting address has been utilized, that an odd starting address has been utilized and an odd number of characters has been received at the I/O device. These cause Or 4 to enable And 5 to indicate an error by means of Or 6 whenever an odd end address is indicated. Similarly, And's 7 and 8 determine that an even number of characters were received starting from an odd address or that an odd number of characters were received starting from an even address. And's 7 and 8 enable Or 9 to permit And 10 to operate Or 6 in the event that an even end address is indicated.

An alternative circuit, and an alternative expression of the device, would determine that the start and ending addresses match or mis-match, and that an odd or an even number of characters were received. Thus, determination can be made on whether any characters were lost enroute and the error signal can be generated.

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