AT&T terminal keyboards?

Hi, All, I just picked up a couple of AT&T terminals, a 730+ and a 5620 "Blit" terminal. The 730+ powers on, passes self-test and probably would work great if I had a keyboard for it. The 5620 lights the CRT but doesn't appear to work outside of presenting a huge green dot the size of the raster. It also lacks a keyboard. I have hopes that it's something simple like wonky internal connectors that need to be reseated (vs bad components). I read on one of the several FAQs that I can use an AT&T 4410 terminal keyboard with the 730+. The box has an 8p8c jack. Additionally, from the same source, I got a 3B1/7300 keyboard and mouse. It happens to have an 8-pin 0.1" female connector in a barbed-lock housing. Outside of the connector, the key layout is superficially the same as a picture I saw of a 730+/4410 keyboard. What I'm curious about is if they are electrically compatible - i.e., could one make an 8p8c->2x4 pin header pin swabber and have the 3B1 keyboard work on the 730+? I won't shocked if they are entirely different, but there are enough superficial similarities that I'm minded to at least ask. I've found the trove of old Blit apps, etc. and see how tortuous the path is to get layers working, etc., but for now, I've got a couple old terminals that are entirely unlike any of the DEC terminals I have, so that by itself is cool. Thanks for any deep knowledge of these guys that isn't already covered on the FAQs. -ethan