That depends on which DEC world you circulated in...
there's been a termcap
entry for the ADM 3A in UNIX for as far back as my experience goes.
I don't recall seeing them at all in non-university or non-UNIX settings,
though. DEC terminals cost enough that in the notoriously cheap educational
market, people gave serious consideration to other forms of terminals (I
have reciepts from the early-to-mid-1980s for VT100s at around $1,700 each,
which is why Software Results had a mix of DEC terminals and CiTOH terminals,
'101's and '101e's).
The ADM3 did not perform cursor addressing, which the ADM3A did, making the 3A
much more useful in many applications - I don't think there would be a termcap
entry for a 3.
Btw, on the off chance that these are 3A's, I'll mention that I have detailed
photos of one, as well as PDF's of both the operators and service manuals posted
on my web site:
http://www.parse.com/~ddunfield/museum/index.html
Look under the "Altair 8800" entry (I use a 3A on the Altair).
Regards,
Dave
--
dave04a (at) Dave Dunfield
dunfield (dot) Firmware development services & tools:
www.dunfield.com
com Vintage computing equipment collector.
http://www.parse.com/~ddunfield/museum/index.html