I bought one of these on ebay quite cheaply, brand new old stock. It seems that there are a lot of them out there.
What i have learned:
1: The four pin connector wants +12vdc on pin 1, ground on pin 4, and pins 2 and 3 are likely signals "A" and "B" in an RS485 differential pair (there is an RS485 line driver on the board; IBM likes using RS485, etc).
2: IBM won't say a word
3: Futaba will tell you that it is an IBM design and to talk to IBM.
4: There are, however, some very similar Futaba displays out there, including the MD202MD08 (without the "A") that people have successfully interfaced in DIY projects.
I'm guessing that this is just an RS485 version of the MD202MD08 and that Futaba is just under NDA with IBM.
I'm hoping, further, that it can be made to work with the PrimeVFD library, here: Arduino Playground - PrimeVfd
It is likely possible to scrape the rs485 driver right off the board and install a max232 module. But I found some chinese ebayer who sells rs485 to ttl modules for like a buck, so i have one on order.
I paid $6 shipped on ebay for an IBM P/N 10N1002 Y-cable providing 3 of the funky 4p4c connectors. As others have found, when i apply 12vdc across pins 1 and 4, it waits a bit and then displays "U001".
It's very easy to open the case. just squeeze gently along the bottom of the back of the case, where the vents are, and lift it apart. Three screws hold the display to the front of the case. There is room enough in here for an arduino nano or whathaveyou if you wanted to embed something right in it.
It's probably possible to remove the IBM connector and replace it with a DB9 or RJ45 but this would require unsticking the glass from the board and i don't want to do that just now.
Evidence found so far:
You'll notice that both of these comments, and the PrimeVFD info, refer to it's slowness and complexity.
So, well, Noritake modules are better. But who cares, i have this giant Futaba and i want to use it.