Old military board? Metal AT connector, have seen these on eBay before but don't know what they are.
Interesting keys on it!
Mhmm.... where have I seen this layout before...
(IBM did make some with numpads instead of the PF block)
You'll find that some of your 122 key boards will have similar key markings.
Your average IBM Rubber dome RJ-11 keyboard right?
No! It has buckling springs! Haven't seen any like this before!
An M2 for the 3153 terminal.
I may edit this post further as I see more interesting stuff.