From mboxrd@z Thu Jan 1 00:00:00 1970 From: dave@horsfall.org (Dave Horsfall) Date: Thu, 31 May 2018 08:46:46 +1000 (EST) Subject: [TUHS] Serial Interfaces (was ^T and Top) In-Reply-To: References: Message-ID: On Wed, 30 May 2018, Clem Cole wrote: > Right - you have to escape things and it is a real mess.  I have seen > some of the SI/SO/DLE stuff in mechanical systems like ticker tape.  I > never saw a real 8-bit interface try to do it and succeed -- its messy > and suspect when data overruns occurs all hell break loose.  By the time > of 8 bits and speed of 9.6K protocol's like UUCP, or IP over serial did > not even bother.  I suspect in the old 5-bit baudot code times, it was > more popular to get a larger character set, but the speeds were much > slower (and the UART not yet invented by Gordon Bell).​  Actually, the closest I've seen DLE being used was in SLIP and PPP; if you needed to send a Frame End then it was escaped with (I think) 0xFF, and that in turn was escaped. All it took was a finite state machine... Of course, those links used RTS/CTS, but you had to flag the end of a frame (packet) somehow. -- Dave