[HECnet] Connecting an HP Itanium BL860c to HECNET... without ethernet

[Paul Koning]

> 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