I don't have a clue what it is that you're describing.... if "CX" is a model number for a modem, you must have the only one in existence.
Please open Device Manager, double-click the modem, click the Details tab and give me the hardware id string (eg: the 1st. line of text that begins with PCI\VEN)
It also helpful if you state whether it's a retail modem or OEM. If the latter, you need to state what computer brand and model it came installed in and say whether it's a desktop or laptop pc.