When running linux, you sometimes want to connect to a cell phone (using it as a modem) over bluetooth.

Different cell phones use different RFCOMM channels to export their Dial-up Networking service on.

Here are the commands to use to find which channel you should use:

hcitool scan – This command gives you a list of all the bluetooth devices in the area, and their associated BDADDR's. Look for your phone, and note the BDADDR.

sdptool search –bdaddr <YOUR_BDADDR> DUN – This command will return the correct channel to use, with a result something like this:

Service Name: QC Dial-up Networking 

Service RecHandle: 0x10007 

Service Class ID List:   "Dialup Networking" (0x1103) 

Protocol Descriptor List:   "L2CAP" (0x0100)   "RFCOMM" (0x0003)     

Channel: 8 

 Then you can set up an rfcomm.conf file as follows (Note the use of Channel eight):

 rfcomm0 {         

# Automatically bind the device at startup         

bind yes;          

#LG CU500         

device  00:19:A1:51:1D:FC;         

channel 8;           

# Description of the connection         

comment "Jay's Phone"; 

}