T320C indeed is capable of tuning DVB-C but the question is if programmers could add another BDA driver so that it can declare itself also as a DVB-C device or add a switch that would change T to C as renzz said.
There are cards like that that report themselves as two devices, but they are just one and can play just one dvb C or T or T2 standart at the time.
Hope thats understandable ;)