As said before, just get one modem in Originate mode, and the other in Answer mode and go from there. Most "modern" modems (that have some Part 68 certification) can do this quite easily as long as you have access to the command stream on each side. The more difficult is when you don't (usually on one side). Then you attempt to get the "answering" modem in answer mode sending its carrier before he "originating" modem asks for it, and will sense it when it wants to. The part that is touchy is making the timeout on the "answer" side long enough. Ob ClassicComp: I should really try this with my Bell 103A modem (I got one, don't ask!) to see if I can get it to "connect". It might need some DC voltage optical couplers!). What an experiment to do! If you want to make two "500" sets talk to each other, a nice 6 Volt battery works quite well placed in series with the two sets. It won't make them ring, but you CAN talk. Use a lantern battery (or 4 D cells) and unless you are making DTMF (touch-tone) on a polarity sensitive set (older 2500 sets) polarity makes little difference. -- Sorry, No signature at the moment. ____________________________________________________________________________________ Never miss a thing. Make Yahoo your home page. http://www.yahoo.com/r/hs