Hi Mike.
I followed your latest advice and the RRC control unit is now working fine via LUMIA 800 and connected to radio (using ports 13000-13002).
The main issue I think was that I had to delete the IP etc static values, used for my home router, on all the fields below DHCP one, since phone is now giving IP on different net, the RRC was connected to phone but the PWR led was still blinking.
Then I tryed the fixed IP of radio location in the SIP contact field and the PWR led stop now blinking (after approx. 30 blinks!) and connection to radio site estabished.
So, my remaining issue is how to overcome the DNS request rejection by phone and/or GSM provider?
Once again asking for your advice...
73 Costas
SV1DH