When I tried to hook it up to my Altair-Duino, I found that the DSR to be asserted or it doesn't think that it's online. I had a choice between cannibalizing one of my serial cables, or making my own. I decided to make my own.
I found a place online that sells DB-25 connectors and bought some male and female connectors.
The Silent 700 has a female connector. So I took one of the male connectors and started on that end.
I looped back DSR/DTR and CTS/RTS (not known if that's needed, but I did it just in case).
RTS/CTS are pins 4 and 5.
DSR/DTR are pins 6 and 20.
A co-worker told me about "security wire". This is nice stuff for my projects. 4 wires wrapped in one cable. The stuff that I got was solid, making it easy to solder into the DB-25 connectors.
I connected wires from pins 2, 3 and 7 (Transmit/Receive/Ground) of the Silent 700 to pins 2, 3 and 7 on the other end of the serial cable that I was creating. One thing that I learned is that the pin numbers on the female end are opposite the numbering on the male end.
I also needed a DB-25 to DB-9 adaptor to connect the home-made cable to the Altair-Duino. I probably should have gotten DB-9 connectors instead, but I wasn't thinking and I had the DB-25/DB-9 adapter laying around.
The problem that I ran into was that I soldered pin 1 on the Silent 700 side to pin 1 on the other end. The DB-25/DB-9 adapter linked that to pin 2 for some reason. De-soldering the pin from the Altair-Duino end solved that problem.
I won't go into setting up the Silent 700. It doesn't support 8-bit communication. I set it for 7-bit, even parity. Then I went through putting those settings into the Altair-Duino through their instrtuctions (https://www.altairduino.com/2017/06/03/serial-device/).
And I now have a new retro-computing toy to play with.
