IBM Model M keyboard for 3192

[Charles Dickman]

I got a box of miscellaneous model M keyboards last week. One of them
has 122 keys and the connector is the size of a PC/AT type circular
DIN connector, but the 5 pins are spread over 240deg instead of the
AT's 180deg. The part no. is 1390702 and a little research found it is
from an IBM 3192 terminal.

Is it electrically/protocol compatible with the PC/AT and PS/2
keyboard or a different animal completely?

-chuck