root@alkos333_TPT60:~# cat /etc/bluetooth/rfcomm.conf 
#
# RFCOMM configuration file.
#

rfcomm0 {
#       # Automatically bind the device at startup
        bind yes;
#
#       # Bluetooth address of the device
        device 00:1C:CC:31:5F:AD;
#
#       # RFCOMM channel for the connection
        channel 3;
#
#       # Description of the connection
        comment "BlackBerry 8830 (alkos333_BB8830)";

root@alkos333_TPT60:~# sdptool search DUN
Inquiring ...
Searching for DUN on 00:1C:CC:31:5F:AD ...
Service Name: Dialup Networking
Service RecHandle: 0x10002
Service Class ID List:
  "Dialup Networking" (0x1103)
  "Generic Networking" (0x1201)
Protocol Descriptor List:
  "L2CAP" (0x0100)
  "RFCOMM" (0x0003)
    Channel: 3
Profile Descriptor List:
  "Dialup Networking" (0x1103)
    Version: 0x0100