You definitely need IMS software and from my own personal experience, you will at some point need the LONSTALK adapter. There are jobs that have the UIT (lcd unit) but the IMS is such a great tool to have for many other Thyssen products as well.
Most tac 20s dont have UIT or inspection switches in the controller. That would be the tac 22. Overall good running units. Also matters which door board you have. The 6300 Ge4 does not have a UIT but if it has the 6300 ABn1 then it has a UIT. If it does have the GE4 board you will need fast tool or door fast to set it up change parameters and do a door scan. The 6300abn1 boards do lose the door scan if you cut the power but with the UIT it takes a matter of seconds to do the scan. The tac 20 uses the 16 bit IMS. There are some 16 bit ims clones on the market. I believe we installed some units with the linear door operators on them but I dont have much on those. good luck