I didn't know Thyssen ever claimed the TAC50-04 was "non-proprietary," even with a UIT. I think a TAC50-04 with a UIT is more of a novelty than anything else. The capability is built into the CPUA card to make the TAC32 non-proprietary. I know of only 2 jobs that came with them, both some of the first 32 bit MODs, and only half of those ever worked.
But if you get the UITs to work or not you will need 32 bit IMS to keep those cars running, either the standard CPUA version (9 pin) or the Ethernet. I don't think the 16 bit CPUs had a plug for a UIT but the easiest way to identify a 32 bit CPUA card is the USB and RJ-45 plugs on the top.
