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Browse Prior Art Database

Display Form for Nondisplayable Characters

IP.com Disclosure Number: IPCOM000076001D
Original Publication Date: 1971-Dec-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Dumstorff, EF: AUTHOR [+2]

Abstract

In data processing systems using extended binary-coded decimal interchange code format, it is not possible to display all characters with the character set commonly available on displays and printers.

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At least one non-text object (such as an image or picture) has been suppressed.
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Display Form for Nondisplayable Characters

In data processing systems using extended binary-coded decimal interchange code format, it is not possible to display all characters with the character set commonly available on displays and printers.

This system utilizes a display based on a 7 x 9 dot matrix, for example, a cathode-ray tube or a matrix printer. When the content of a storage unit 1 is to be displayed, the characters for which graphics are available are printed in normal fashion. When characters are detected for which normal graphics are not available, an alternative display mode is entered.

Instead of going to a read-only memory or a character generator 2, the character in the output register 3 is gated directly to the display control circuits 7 which control the dots in the row positions.

This gating is accomplished by an invalid character detector 5, which switches the input 6 to the display control circuits from the character generator to connect directly to the output register. At the same time, the invalid character generator supplies a signal to the display control circuits 7, which is effective to fill columns 3 and 5 of the display matrix.

The drawing illustrates the portrayal of a Hexadecimal B according to this concept. The horizontal rows correspond to the bit positions in the character. A 1 in any bit position results in a corresponding row of dots. Columns 3 and 5 may also be filled with dots when displaying in this mode to avoid confusion w...