Comment by toast0

7 bits isn't that odd. Bauddot was 5 bits, and found insufficient, so 6 bit codes were developed; they were found insufficient, so 7-bit ASCII was developed.

IBM had standardized 8-bit bytes on their System/360, so they developed the 8-bit EBCDIC encoding. Other computing vendors didn't have consistent byte lengths... 7-bits was weird, but characters didn't necessarily fit nicely into system words anyway.