assuming you already have the old end de-solderd off the mic strip back a little bit of the mic cover cord first thing you want to look for is the shield wire (the bare wire with no plastic covering).. you will find it wrapping around another wire. now 99.99995% of the time that wire that it is wrapped around IS THE AUDIO WIRE!!! you already have two down.... now take your multimeter and put the negative probe on the shield(ground) and place it on one of the other existing wires. if it beeps with out you keying up the mic that will be you RX wire if it doesn't beep key up the mic if it beeps it is your TX wire. and repeat the steps for the other remaining wire to double check if it is correct. now wire up the end according to what you have found and what the radio specs are... easy stuff huhh?
