Yes, it's explained on that link posted above (
http://www.kc8unj.com/radar/). You can either build a custom V1 to Serial cable or plunk down $39 for a very nicely made TTL2USB box, and another $10 for a V1 to TTL2USB cable.
I'm opting for the home-built serial cable, since flat Cat-3 is very easy to run through the car
The only thing I'm stuck on is one component on the
schematic that shows 5.1V value. Does anyone know what that symbol is for? RatShack has all the needed parts and they're easily accessible.
EDIT: Nevermind.. found it... zener diode