In the client mode, this required option specifies the address of the remote RFCOMM server. In the server mode, this option can be used to specify the local address to listen on. By default, server will listen on ANY address. The address can be specified as BD_ADDR or name. If name was specified then the rfcomm_pppd utility will attempt to resolve the name via bt_gethostbyname(3).
In both client and server modes, this required option specifies RFCOMM channel to connect to or listen on. In the server mode, RFCOMM channel should be a number between 1 and 30. In the client mode, RFCOMM channel could either be a number between 1 and 30 or a service name. Supported service names are: DUN (for DialUp Networking service) and LAN (for LAN Access Using PPP service). If service name was specified instead of numeric RFCOMM channel then rfcomm_pppd utility will try to obtain RFCOMM channel for the service via Service Discovery Protocol.
Act as an RFCOMM client. This is the default mode.
Do not detach from the controlling terminal, i.e., run in foreground.
Display usage message and exit.
In both client and server modes, this required option specifies which ppp(8) label will be used.
In the server mode, register the Serial Port (SP) service in addition to the LAN Access Using PPP (LAN) service. It appears that some cell phones are using the so-called ""callback mechanism"". In this scenario, the user is trying to connect his cell phone to the Internet, and users host computer is acting as the gateway server. It seems that it is not possible to tell the phone to just connect and start using the LAN service. Instead, the users host computer must ""jump start"" the phone by connecting to the phones SP service. What happens next is the phone kills the existing connection and opens another connection back to the users host computer. The phone really wants to use LAN service, but for whatever reason it looks for the SP service on the users host computer. This brain damaged behavior was reported for Nokia 6600 and Sony/Ericsson P900.
Act as an RFCOMM server.
This option maps directly onto -unitppp(8) command line option and tells rfcomm_pppd to instruct ppp(8) to only attempt to open /dev/tun N. This option only works in the client mode.