After a lot of googling debugging and struggling I have found how to connect to Internet through H3G UMTS using LG U310 handset (I think it could be the same for U300 too).
The first you need to check, is the phone settings for DUN, in the phone menu go to Connectivity->3.Dial-up network->2.Bluetooth should be checked.
I am not sure, but may be you need to change also the data port, on the idle screen type 566366#*# and you are in the technical menu, go to 3.Port Settings->2.Data Setting and make sure 2.BT set for Data is selected.
Make sure the phone has no applications in background (press and hold Menu button to pop-up the “task-bar”) or you will have some cryptic errors about phone is busy.
Now, as soon as you get the phone with idle screen – pair it:
`hcitool scan` - should discover your handset and show its "MAC" `hcitool cc "MAC"` - does some connection stuff `hcitool auth "MAC"` - authenticates
a window with PIN request on both PC and handset may pop-up at this point or the next one
Now connect to the PPP channel (channel 8 is PPP):
`rfcomm connect rfcomm "MAC" 8` - should give you: Connected /dev/rfcomm0 to "MAC" on channel 8 Press CTRL-C for hangup
Now to the hard point, PPPD:
This is my peer file /etc/ppp/peers/u300:
debug noauth #may be commented out if you want PPPD to configure the default gateway defaultroute usepeerdns ipcp-accept-remote ipcp-accept-local 460800 crtscts connect "/usr/sbin/chat -v -f /etc/chatscripts/tre" /dev/rfcomm0 115200 noccp novj lcp-echo-interval 0 lcp-echo-failure 0 921600 noipdefault
and the magic chatscript /etc/chatscripts/tre:
ABORT BUSY ABORT 'NO CARRIER' ABORT ERROR REPORT CONNECT TIMEOUT 10 "" rAT OK ATE1 OK 'AT+IPR=115200' OK 'AT+CGDCONT=1,"IP","","",0,0' OK ATD*99# TIMEOUT 22 CONNECT ""
when you’ve got your files in place lauch pppd:
pppd file /etc/ppp/peers/u300
and watch the log….
hopefully you’ll get something like: log file