Procom + is the terminal emulation program used to program IDS systems. So, we know you have an IDS. The question is what size. If it is a larger one, yes they support T1 and/or PRI card. The trouble is that the system has not been manufactured or supported for some time (Intertel bought Executone and immediately stopped producing new parts). They did not make many PRI cards and those they did make have been slowly blowing.
The end result being that PRI cards are extremely rare and extremely expensive. I have not looked lately but I would not be surprised if you ended up paying in the mid to high 4 figures for a PRI card.
T1 cards are a bit more common and so a bit cheaper (but still expensive). If you do buy one make sure it comes with the clock cable or you will be out of luck.
As an aside, if it is a small IDS (IDS 42 or IDS 84) you are out of luck.