bit-paired keyboard

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

