Should I install modem drivers, utility and application?

My studio 1535 laptop doesn't have a built in modem but it came with software for a conexant d400 external modem, which I think was on it originally.

I have since reformatted the hard rive and reinstalled vista.

Now I am wondering if I should install the driver, application and diagnostic utility for this conexant external modem in case I need to send faxes. Apparently it would help to control an external usb modem, but would it have to be a particular brand of dell modem or will this software and driver be suitable for any extrenal usb modem that I might get? Or should I wait and if I buy some modem would it come with its own set of software?

The only reason I see for a modem is if I needed to send a fax or if I was somewhere where there was only a modem connection, but since the laptop doesn't have a telephone type socket to connect a phone line, I would only be able to do any of this if I already had a usb modem to make the connection between a phone line and the laptop.

I do have an Apple usb external modem which I use on my Mac Pro desktop. Would this modem be suitable to use with my dell laptop?

It didn't come with any software because I think it's built into the Mac OS. 

Thanks for any advice.