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===DEC SIXBIT code<span class="anchor" id="DEC six-bit code"></span>===
A popular six-bit code was [[Digital Equipment Corporation|DEC]] SIXBIT. This is simply the ASCII character codes from 32 to 95 coded as 0 to 63 by subtracting 32 (i.e., columns 2, 3, 4, and 5 of the ASCII table (16 characters to a column), shifted to columns 0 through 3, by subtracting 2 from the high bits); it includes the space, punctuation characters, numbers, and capital letters, but no control characters. Since it included no control characters, not even end-of-line, it was not used for general text processing. However, six-character names such as [[filename]]s and [[assembly language|assembler]] [[identifier|symbol]]s could be stored in a single [[36-bit]] word of the [[PDP-10]], and three characters fit in each word of the [[PDP-1]] and two characters fit in each word of the [[PDP-8
Another, less common, variant is obtained by just stripping the high bit of an ASCII code in 32 - 95 range (codes 32 - 63 remain at their positions, higher values have 64 subtracted from them). Such variant was sometimes used on DEC's [[PDP-8]] (1965).
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==={{anchor|ECMA-1}}ECMA and ISO six-bit code===
A six-bit code similar to DEC's, but replacing a few punctuation characters with the most useful control characters—including [[Shift Out and Shift In characters|SO/SI]], allowing code extension—was specified as [[Ecma International|ECMA]]-[https://ecma-international.org/publications-and-standards/standards/ecma-1/ 1] in 1963
{|{{chset-table-header1|ECMA-1 and ISO/R 646:1967}}
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