FEATURES of the 1977 AJ 841 I/O:
- ASCII code
...
- Off line use as a typewriter
via https://terminals-wiki.org/wiki/index.php/File:AJ841IO_Ad_1977.jpg
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The line you are (were) on or off of, was the current loop. This is 1960's/1970's (Teletype Corp ASR-33, but the line goes back to the earliest days of telegraphy wires strung long distances outside).
"ON LINE" means your teleprinter is wired in series with a constant-current loop; breaks the current signalled characters which the printer printed. The keyboard, wired in series with the printer, could induce characters.
These were half-duplex; at any moment, send or receive, not both. Or, typing, it printed locally and remotely. One pair of wires, 60 milliamperes at 100 volts (or so) comprised the loop. (The ASR-33 usually jumpered for a mode modern 20 mA).
@liaizon I remember my mom using the term about the bank she worked at in 1978 or sth
@liaizon line printers! like telegraph right?
@window the reference I had here was for a terminal. so not a telegraph but for talking to a room sized computer
@liaizon im just thinking of where it coulda been used earlier. being "on" the line connected to the telegraph messages streaming in, vs disconnecting and typing some tape yourself? idk actually maybe this is an interesting one for @tomjennings
@liaizon I was widely taught about offline processing in high school (lots of data was entered offline and sent to punched cards and spools of tape, and those were physically collected and processed in batches on a computer which could be some distance away).
This is still used to some extent even today, its why if you want to change your car registration details in Britain you still have to do them during daytime to early evening as the systems are locked off from data changes after about 1900 whilst the batch processes are run..
I hadn't realized the term `offline` was so much older them me.