On Mon, Jan 22, 2024 at 11:39 PM segaloco via COFF <coff@tuhs.org> wrote:

Howdy folks, just finished an exciting series of repairs and now have a DEC VT100 plumbed into a Western Electric Data Set 103J. I was able to supply an answer tone (~2250Hz) at which point the modem began transmitting data. I could then pull the answer tone down and the connection remained, with keypresses on the VT100 properly translating to noise on the line.

Really all I have left is to see if it can do the real thing. I'm keeping an eye out for another such modem but in the meantime, is anyone aware of any 300-baud systems out there in the world that are currently accepting dials in? I don't have POTS at home but they do at my music practice space and if there is such a machine out there, I kinda wanna take my terminal and modem down there and see if I can straight up call a computer over this thing.

There are plenty to be found, so I'm not going to answer that question directly but offer a slightly different possibility, which might make debugging easier.

If you have a second (known working) modem, get something like the Viking DLE-200B, which is about $125 or less on eBay/Amazon or the like.

It will simulate a traditional POTS line -- has two RJ11 ports in it.

I used to have access to a similar unit a few years ago (it actually could support 4 lines, IIRC), but for your purposes, I suspect it will work. But that makes everything a closed system under your control.

Clem