[GreenKeys] Generator, DC Signalling No 1

[Sam Hallas]

I've had an e-mail from Alf Fisher of the Signals Museum at RAF Henlow,
which is just a few miles up the road from where I live.
Signal Generator

In their collection they have this device which you can see on my web
page at:
http://www.samhallas.co.uk/greenkeys/index.htm

Can anybody help Alf with technical information on how to connect this
piece of kit up?

Cheers,

Sam Hallas
G8EXV