On Apr 19, 2013, at 10:29 AM, Bob Armstrong wrote: 5 bit is what radio amateurs call RTTY ... 5 bit code is Baudot (as in Emile Baudot, the guy who invented it). It predates both ASCII and EBCDIC and was the standard for the wire services way back when they used real Teletypes connected by leased phone lines. I think it's more Telex (like telegrams), and selected other communications services like weather data transport that used 5 bit code. Wire services, as in the people feeding stuff to newspapers, were generally 6 bits rather than 5. The 6 bit codes came in many flavors (for example, the stock wire had its own code with lots of dedicated codes for different fractions). I did some work in the late 1970s on PDP-11 software for Typeset-11 that handled the interface between these 6 bit data streams and the 8-bit codes used internally in Typeset-11. paul