Haven't bought the gps unit yet, but the one I'm probably going to buy is either bluetooth (too much work for me to learn how to use that with a pic) or usb as it's designed for use with a pda
I'm guessing it might be some kind of serial output using the usb connector, but it's unlikely i'll be that lucky.
According to the user manual, there are 3 types of cable/connector, USB, PS2 and RJ45 http://www.transystem.com.tw/pdf_gps..._Rev%201.3.pdf