Mutley, You can get an idea if data is flowing between PAW and Skyview from the Serial Port configuration page (SETUP MENU > SYSTEM SETUP >SERIAL PORT SETUP), if you look at the TX & RX & Error Counters . You can also take a screenshot to a USB stick at any time by pressing buttons 2 & 7 simultaneously (Page 21,2 of the Installation Manual explains this and how to download various error logs), which can be useful in debugging the system
I have attached a screenshot from one of my tests when I was troubleshooting my installation, that showed a problem. I have also attached a copy of my D37 Connector cabling, showing the wiring connections I was using for Serial Port 2. I'll take a screenshot of my working configuration when I am next at the airport.