A heads up ...
Joerg Hoppe (
http://retrocmp.com/projects/blinkenbone) has a very useful set of tools for reactivating control panels of old systems.
It consists of
1 a beaglebone black, a "cape" for the beaglebone that provifes RS232.
2 a blinkenboard driver. This allows some 128 lines to be used as inputs and outputs to be driven/sensed under the control of the beaglebone black. They can drive low or high voltages (in groups of 8 for hi volts, or 8 for low volts)
He has good simple software and network APIs to allow the boards to be controller. (as well as the RS232)
I have used this to bring an old PDP 11/70 panel back to life. I am working on a saratov-2 front panel and a PDP-8 front-panel at present.
The beaglebone can run SIMH - and so you have a unix emulator available to drive the panel.
If you have lights and switches to drive/read his toolkit is a quick way to get started.
11/70 - panel
http://www.scotnet.co.uk/iain/DEC/1170/saratov-2 - panel
http://www.scotnet.co.uk/iain/saratov/http://www.scotnet.co.uk/iain/saratov/font-panel.jpg