> One used to (in the 1970s) be able to purchase off-the-shelf "long > haul" modems that converted between EIA signal levels and > current-loop. Sometimes called "line drivers", because that's not confusingly overloaded terminology or anything. I was about to say "e.g. Gandalf LDS family", but iirc those were actually _leased_, not purchased.
> If the 25-way DSUB connector bothers you, have a look at RS-449, > which employs a 37-way (DC37) connector Some may be amused to remember that the DB/DC/... family of connectors were known as "D-subminiature" when introduced. De
