How to setup Bluetooth

This is a subjective story about my experiences connecting a ThinkPad T43 running Gentoo and a Nokia N70 using Bluetooth, but I suppose most of the stuff here is generic stuff about how to connect laptops with linux with cellphones using bluetooth.

The kernel used was 2.6.14-gentoo, patched up to get the SATA working after suspend-to-memory.

BlueZ Installation

First of all, installation of Bluez; the following gentoo ebuilds was installed:

• net-wireless/bluez-bluefw
• net-wireless/bluez-firmware
• net-wireless/bluez-hcidump
• net-wireless/bluez-hciemu
• net-wireless/bluez-libs
• net-wireless/bluez-utils

net-wireless/bluez-kernel was also installed, but later I read it should not be needed when running 2.6-kernel - it could even be harmful.

Configuring the kernel

Since the Bluetooth card is connected to the USB subsystem, you will need to enable USB support in your kernel and load the according modules.

# modprobe uhci_hcd ; modprobe ehci_hcd

In the kernel configuration, I turned most of the bluetooth stuff to <M>; it can be found in the Networking section of the linux configuration.

NOTE!

"RFCOMM protocols support" and "RFCOMM TTY support" (CONFIG_BT_RFCOMM and CONFIG_BT_RFCOMM_TTY) have to be built into the kernel (and not as a module), and hence "Bluetooth support" (CONFIG_BT) and "L2CAP" (CONFIG_BT_L2CAP) also have to be configured as built-in.

I found an explaination at http://www.gentoo.org/doc/en/bluetooth-guide.xml about how to set up Bluetooth in Gentoo. I followed most of the steps, but be particularly aware of the notes above on kernel configuration.

Serial connection over Bluetooth

One of the reasons for getting that bluetooth connection up was to be able to use GPRS or 3G (UMTS) for connecting my laptop to internet. I was googling a bit on it, and I was pretty surprised to learn that one should communicate with the modem using AT-commands - that's stuff we did in the previous millenium, causing our modems to make lots of fancy sounds. By configuring /etc/bluetooth/rfcomm.conf correctly, I got a device /dev/rfcomm0 - eventually one could use the command:

rfcomm bind 0 00:15:A0:7A:90:F2 3

Where the HW address should be replaced with that of your phone - if you don't know the hardware address of your phone yet, you can find it running:

hcitool scan

and '3' is the channel to use. I spent quite some time fighting before I found out of that one; I didn't find it documented anywhere, but by running

sdptool records 00:15:A0:7A:90:F2

I found channel 3 to be the right one for my phone. Some guides suggested "1" as value without any explaination. By experimenting, I managed more or less to crash the bluetooth stack on the cellphone so it had to be rebooted.

Now that /dev/rfcomm0 exists, one can try to access it i.e. by using minicom:

minicom -s

set the serial device to be '/dev/rfcomm0', chose 'exit' and then the AT-commands can be typed in. With my operator (Telenor, Norway) it seemed simple enough, I just entered

ATDT *99#

and lots of cryptic letters started dancing across the screen, indicating a ppp session startup.

Then, to run pppd - I created /etc/ppp/peers/nokia with particularly those lines:

/dev/rfcomm0

connect '/usr/sbin/chat -v -f /etc/ppp/chat-nokia'

debug

10.0.1.3

crtscts

noipdefault

ipcp-accept-local

defaultroute

novj

nobsdcomp

novjccomp

nopcomp

noaccomp

usepeerdns

and a simple /etc/ppp/chat-nokia

'TIMEOUT' '5'

'ABORT' 'BUSY'

'ABORT' 'ERROR'

'ABORT' 'NO ANSWER'

'ABORT' 'NO CARRIER'

'ABORT' 'NO DIALTONE'

'ABORT' 'Invalid Login'

'ABORT' 'Login incorrect'

'ATZ'

'OK' 'ATDT*99#'

'~--'

and then I entered

pppd call nokia

and I got Internet.

Different network operators may require different call strings; I guess I'm lucky that "*99#" works without additional parameters.

For doing anything else, I think gammu is the best option, though I didn't get it to communicate with my phone yet.

External Links

http://gagravarr.org/series-60/

http://www.polycon.fi/~laa/biblo/linux_gprs.html