bit-paired keyboard

bit-paired keyboard

(hardware)(Obsolete, or "bit-shift keyboard") A non-standardkeyboard layout that seems to have originated with theTeletype ASR-33 and remained common for several years onearly computer equipment. The ASR-33 was a mechanical device(see EOU), so the only way to generate the character codesfrom keystrokes was by some physical linkage. The design ofthe ASR-33 assigned each character key a basic pattern thatcould be modified by flipping bits if the SHIFT or the CTRLkey was pressed. In order to avoid making the thing more of aRube Goldberg kluge than it already was, the design had togroup characters that shared the same basic bit pattern on onekey.

Looking at the ASCII chart, we find:

high low bitsbits 0000 0001 0010 0011 0100 0101 0110 0111 1000 1001010 ! " # $ % & ' ( )011 0 1 2 3 4 5 6 7 8 9

This is why the characters !"#$%&'() appear where they do on aTeletype (thankfully, they didn't use shift-0 for space).This was *not* the weirdest variant of the QWERTY layoutwidely seen, by the way; that prize should probably go to oneof several (differing) arrangements on IBM's even clunkier026 and 029 card punches.

When electronic terminals became popular, in the early1970s, there was no agreement in the industry over how thekeyboards should be laid out. Some vendors opted to emulatethe Teletype keyboard, while others used the flexibility ofelectronic circuitry to make their product look like an officetypewriter. These alternatives became known as "bit-paired"and "typewriter-paired" keyboards. To a hacker, thebit-paired keyboard seemed far more logical - and because mosthackers in those days had never learned to touch-type, therewas little pressure from the pioneering users to adaptkeyboards to the typewriter standard.

The doom of the bit-paired keyboard was the large-scaleintroduction of the computer terminal into the normal officeenvironment, where out-and-out technophobes were expected touse the equipment. The "typewriter-paired" standard becameuniversal, "bit-paired" hardware was quickly junked orrelegated to dusty corners, and both terms passed into disuse.