hello!
easyer and faster is to solder all connector pins to IC socet and try all possible combination in less than 30min.
here is how i do this:
http://forum.gsmhosting.com/vbb/show...8&postcount=18
also, need to remmber that in some models Tx, rx wires is not connected to system connector, but to test points on PCB (which is sometimes even marked)