No, it's not.
That stuff is left over from 1940s-1950s schemes for polled multidrop teletype machines - multiple stations on one wire, taking turns. The idea was that you punched paper tapes locally and then put them into a reader. When it was your station's turn, the central machine would send a polling sequence of a few characters, the selected reader would start up, read one message into the upstream system, then stop. In the other direction, the central station could send a turn-on code to any machine, print a message, then turn it off. Only one machine at a time could run. Those control characters were the delimiters for that process. All of this was mechanical, done by a unit called the "stunt box", which you can look up if really bored.
RS-485 is a descendant of that technology, still used in some industrial control systems.
(I used to restore antique Teletypes for fun, and had a functional Telegraph Office at steampunk conventions for about seven years.)