Connecting Linux to the Internet via Bluetooth and GPRS

After I bought my Nokia 6681 phone, I spent some time trying to figure out how to connect my notebook to the Internet through a bluetooth connection using GPRS. All I needed were some initialization strings to the bluetooth modem of my phone and the ppp network configuration of my phone company, Claro. I had no luck on Nokia's manuals and Claro did not even knew what I was talking about (although there is no way I can guess what are their configuration…).

After "googling" a lot, I managed to find a working configuration. There are many configurations out there, all hard to find and many do not work… Here is the configuration that works for me. If you have another, feel free to edit this page and add it.

This configuration worked on my Debian Lenny system, please adjust to your distribution.

The first thing is to configure a virtual serial port, that will be connected via bluetooth to the phone and work as a GSM modem. After you have your blueooth device working, try:

root@morpheus:~# hcitool scan
Scanning ...
       00:E0:03:1D:CD:FD       link
root@morpheus:~#

To find your phone's MAC. Here is my Nokia, its name is link.

Insert something similar to the following to /etc/bluetooth/rfcomm.conf:

rfcomm0 {
       # Automatically bind the device at startup
       bind yes;

       # Bluetooth address of the device
       device 00:E0:03:1D:CD:FD;

       # RFCOMM channel for the connection
       channel 1;

       # Description of the connection
       comment "link";
}

Adjust the device and comment to match your phone. This will make /dev/rfcomm0 virtual serial device to automatically connect to the phone when it is opened for reading. So, the modem will just "be there" when you need.

PPP set up is quite simple when you already know the parameters… Add something like the following to etc/ppp/peers/claro (change the name of the file claro to one name suitable for you):

/dev/rfcomm0
connect "/usr/sbin/chat -v -f /etc/chatscripts/claro"
defaultroute
replacedefaultroute
lock
debug
noauth
noccp
persist
user claro
password claro
usepeerdns
noipdefault

It basically will configure automatically all network parameters when connected and point to a chat script (explained below).

• Note the /dev/rfcomm0 setting, pointing to the bluetooth modem.
• The debug setting is useful to detect problems (pppd will print debugging to syslog, on Debian at /var/log/syslog).
• My ISP seems to work with deflate compression (enabled by default), if you have problems add the option nodeflate. I also added noccp, since my ISP rejects it.
• The persist setting will make it try to reconnect if the connection is broken.
• Adjust the user and password to the ones provided by the phone company (they have to give you this information). Try looking for it on you phone's connection settings.

The chat script was the hard part… It was hard to find a working one. Here is the one that works with my Nokia 6681 and my phone company Claro, /etc/chatscripts/claro (also rename it to match one name good for you and matches the pppd configuration above):

'' ATZ
OK-AT-OK AT+CGDCONT=1,"IP","claro.com.br"
OK "ATD*99***1#"
CONNECT ''

The number *99***1# seems to be standard to GSM (I am not sure, if in doubt, ask your company). It is also needed to adjust the string claro.com.br to the one provided by your phone company. This one can be easily found on your phone connection settings.

That's it. You should have a working connection now. Try it with:

fabio@morpheus:~$ pon claro

Where claro is the name of the file at /etc/ppp/peers/. Check out the log information at syslog to see if everything worked fine. To disconnect, just:

fabio@morpheus:~$ poff claro

I believe there is a way to make it work using kppp or other graphical tool, I have not tryed.

I got around 165kbps and a latency of at least 400ms to 4s… In practice, GPRS seems to fail 10% of the times I try to use it. I am not sure if it is Claro's fault or all GPRS are like this.

• BlueZ - Official Linux Bluetooth protocol stack
• PPP for Linux