need help with usb cable

[dninja at gmail.com (Robin Wood)]

Hi
I've just bought a usb cable so I can jtag a Fon router. The cable is
designed for a kyocera mobile and I need to chop the phone end off it
so I can use the tx and rx wires. I'm trying to follow this hack
http://fonerahacks.com/index.php/Tutorials-and-Guides/Cell-Phone-USB-Adapter.html
but unsurprisingly the cable I ended up with is different to the ones
they give examples for.

How can I find out which wires are which?

Robin