focus remote transmitter

I just bought a used 2002 focus that did not come with keyless entry, but it does have power locks. An SE model. Does this car have the transmitter for remotes built in? Or would I have to buy a system for keyless entry? And can I use an old remote from my 1996 contour?

Don't quote me on it, but I'm pretty sure that the entire system is seperate, as the remotes operate on the same frequency...call your Ford dealer to make sure, but you'll most likely have to get an aftermarket unit, and your Contour remotes won't work unless there's some way to change the transmitting frequency of the remote, which there isn't.