On Feb 13, 2015, at 9:06 AM, Clem Cole <clemc at ccc.com> wrote: I agree, I never saw correctly configured systems with anything less than 8 bits. 7 with parity (8 total) as Paul said, was pretty standard. particularly on modems. Early UNIX tty drivers used to assume it and pretty much always AND 0x7F with the input character. Not only that, but some (BSD 2.9?) put out text with 0x80 ORed into the output stream, which messes up modern terminal emulators. Less than 8 does appear in some places. There s the old 5 bit code (Murray and friends, referred to as Baudot or RTTY by hams). There are a pile of 6 bit codes that were used by newspaper wire service data sources, carrying a variety of typesetting codes specific to the data carried. For example, stock data had lots of special codes for all the fractions then used for prices. I did some work on drivers for that, DL11s with an unusual collection of mode jumpers most likely. paul