I've taken some pictures of the inside of the plotter and close-ups of the interface assembly card, which is where most of the wires from the interface connector go to. Perhaps someone will see something that makes sense to them. I also opened up an ASR-33 teletype and looked at the connector where the plotter interface cable plugs in. It is a 9 pin molex connector, with 8 pins being used. I *can* find documentation on that somewhere in one of my teletype manuals. Pictures can be seen at the bottom of: http://www.woffordwitch.com/HP7202.asp Ashley http://www.woffordwitch.com