17 lines
935 B
Plaintext
17 lines
935 B
Plaintext
bit-paired keyboard
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n.,obs. (alt.: bit-shift keyboard ) A non-standard keyboard layout that
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seems to have originated with the Teletype ASR-33 and remained common for
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several years on early computer equipment. The ASR-33 was a mechanical
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device (see EOU ), so the only way to generate the character codes from
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keystrokes was by some physical linkage. The design of the ASR-33 assigned
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each character key a basic pattern that could be modified by flipping bits
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if the SHIFT or the CTRL key was pressed. In order to avoid making the thing
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even more of a kluge than it already was, the design had to group characters
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that shared the same basic bit pattern on one key. Looking at the ASCII
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chart, we find: high low bits bits 0000 0001 0010 0011 0100 0101 0110 0111
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1000 1001 010 ! # $ % ' ( ) 011 0 1 2 3 4 5 6 7 8 9 This is why the
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characters ! #$% '() appear where they do on a Teletype (thankfully, they
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didn't use shift-0 for space).
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