I found out that to get the computer to work with the Radio, you don't connect the cable to the back of the radio.  You connect the Din connector to the back of the control head.  I saw a Youtube video before I did anything.   Having never read the manual, I had my radio working both Packet Radio and Winlink in about 10 minutes from setup.  I would have been pissed had I not seen this.  I haven't tried the back of my radio myself, because once it's working why bother. 

https://www.youtube.com/watch?v=sk8JqGl8vbQ

David, aa6rv