heiff

I'm having a problem with the external modem connection on a Prologix cabinet. I'm using the correct USR 839, set as described in the Avaya docs.

The modem usually drops the call after the first ring (in other words, it doesn't really answer at all). Sometimes it takes several rings, and then drops the call, and very occasionally, it will actually pick up and start to handshake - but drops the call after only a few seconds.

I'm stumped. The problem isn't the modem (I've tried 3 different brand new USR 839 modems and they all do the same thing). I suspected some "quality issues" with the processor interface cable (I'd previously had a bad connection on the DTR wire), so I pulled apart the cable and wired everything onto a punchdown block (connected to the processor with an amphenol connector). Exactly the same results. Could the RS-232 interface on the processor have gone wrong?