After long time tuning my connection - finally it works.
I'm using a BB 8100 Pearl as a GRPS-Bluetooth modem.
These are my configs:
<chatscript>
ABORT BUSY ABORT 'NO CARRIER' ABORT VOICE ABORT 'NO DIALTONE' ABORT 'NO DIAL TONE' ABORT 'NO ANSWER' ABORT DELAYED
# modeminit
'' ATZ
'' AT&F&C1S0=0+IFC=3,1
OK 'AT+CGDCONT=1,"IP","internet.t-d1.de"'
# ispnumber
# OK-AT-OK "ATDT*99#"
OK 'ATDT*99***1#'
# ispconnect
CONNECT \d\c
</chatscript>
<peerfile>
hide-password
noauth
debug
nodetach
/dev/rfcomm0
460800
nodefaultroute
noipdefault
#ipcp-no-addresses
#ipcp-accept-remote
ipcp-restart 7
lcp-echo-interval 0
lcp-echo-failure 0
#lcp-max-configure 2
#lcp-max-failure 2
#mtu 1492
local
user "t-d1"
remotename bt
ipparam bt
novj
nobsdcomp
novjccomp
nopcomp
noaccomp
nomagic
usepeerdns
connect "/usr/sbin/chat -v -f /etc/chatscripts/bt"
</peerfile>
<pap-secrets>
"t-d1" bt "t-d1"
</pap-secrets>
In case of questions, don't hesitate to contact me.
Hope this helps.
Florian