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Odd-Even Relay Checking Devices

IP.com Disclosure Number: IPCOM000098831D
Original Publication Date: 1958-Jun-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Barbeau, RA: AUTHOR [+2]

Abstract

This checking device has relay circuitry for verifying the accuracy of a five place code perforation in a standard teletype tape which is punched under control of an IBM 80 column card. As the tape is punched column by column, the odd or even nature of each count of columnar perforations is sensed.

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Odd-Even Relay Checking Devices

This checking device has relay circuitry for verifying the accuracy of a five place code perforation in a standard teletype tape which is punched under control of an IBM 80 column card. As the tape is punched column by column, the odd or even nature of each count of columnar perforations is sensed.

A number of checking relays is provided to set contacts to detect punch control errors by predetermining and comparing the odd or even nature of each set of perforation bits and the total number of such bits before and after the perforation of each column of the tape. Checking is performed by comparing the odd or even natures of the totals in the code bit count accumulator before and after each operation, adding an odd or even number representing the number of perforations to be punched and those actually punched.

1. Before adding time the code bit accumulator is tested for the presence of an odd or even number.

2. At adding time, the amount being added (column code bit count derived from the card) is tested to determine if it is odd or even.

3. The two foregoing conditions are combined to determine whether the accumulator should contain an odd or even number after adding time.

4. Following adding of bits under punch control, the accumulator is again tested for its total to be compared with the odd and even contacts set according to item 3.

5. A comparison of items 3 and 4 should find odd or even agreement for tape punching to continue....