On Tue, Dec 1, 2015 at 11:55 AM, Paul Koning <paulkon...@comcast.net> wrote: > I'm not sure I understand the question correctly. That article clearly > points out the 20 mA wires, and presumably that's where your ASR33 is > connected. The VT50 comes (according to the peripherals handbook) with a > standard 20 mA interface, optional RS232 interface. So it sounds like it > would be a matter of finding where the 20 mA connector on the VT50 is, and > plugging into that. > > Interestingly enough, the VT52 is listed as supporting either kind of > interface, but only one; "specify at time of order".
I don't know that I've taken apart a VT50 or if there are internal differences, but for the VT52, there's a ~2"x5" (from memory) PCB with interface circuitry for either EIA or 20mA and a permanently-attached cable with the appropriate connector on the host end. You take the bottom of the terminal off, pop the board, pop the other one on and it's switched. It would not be difficult to replicate either board, either by hand or with a fabricated PCB. -ethan
