I got a used IVS2000. I want to know if I can install a CCIS link in it to connect it to an 2400 ICS.

Apparently, back in the old days of that system, they didn't have licences for different features, but they had 'feature set'. 3 levels of those, and only the 3rd level included the CCIS feature. Does anybody know how to find out, what feature set this system came with?

Thanks