This is just an experience I would like to share with users of the N810 in Austria.
I tried to connect to the internet using my Sagen my700X mobile phone. Bluetooth worked immediatly without any problems but he connection to the Internet failed.
Unfortunatly the N810 and the my700X is not supported by the hotline of my mobile provider Mobilkom Austria A1.
Finally I found out the settings to get an Internet connection with A1:
Typ: GPRS
Dial: *99***1#
DNS1: 194.48.124.200
DNS2: 194.48.139.254
Username: ppp@a1plus.at
Password: beliebig (use any string you like)
Modem Init: AT +cgdcont=1,"IP","A1.net"

Note: it is essential to type a blank between AT and +cgd...