10 Dec
2021
10 Dec
'21
9:36 p.m.
On Dec 10, 2021, at 3:29 PM, Thomas DeBellis
<tommytimesharing at gmail.com> wrote:
I know VMS at least did some kind of line. Columbia's chemistry department got a VAX
before the campus Ethernet existed, so that wouldn't have been an option.
However, I can't remember whether it was a synchronous or asynchronous connection;
only that the 'wire' went into one of our DN20's (I think CU20B). I think the
'wire' had modems on both sides, but I can't remember what those were, either.
The mainstream comm link before Ethernet was the DMC-11 or DMR-11. Async DDCMP is a low
cost alternative (with lower performance). You'd tend to find it in embedded
applications, which is why it's a key part of RSX. And it appears in devices like the
VT71 typesetting terminal.
RSTS/E did not do async DDCMP for a long time; I added it at some point to get DECnet onto
the Pro. That was unofficial; in V10.1 it became part of the regular release but even
there it is a bit clunky and not quite complete. But it's enough that you can get
DECnet/E to use a terminal line.
paul