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:

Device Drivers → USB support → <M>Support for Host-side USB (CONFIG_USB)

Device Drivers → USB support → [*]USB device file system (CONFIG_USB_DEVICEFS)

Choose an appropriate USB host driver, one of:

Device Drivers → USB support → <M>EHCI HCD (USB 2.0) support (CONFIG_USB_EHCI_HCD)

Device Drivers → USB support → <M>UHCI HCD support (CONFIG_USB_UHCI)

Device Drivers → USB support → <M>OHCI HCD support (CONFIG_USB_OHCI)

Enable Bluetooth subsystem and drivers:

Device Drivers → Networking support → <*>Bluetooth subsystem support (CONFIG_BT)

Device Drivers → Networking support → Bluetooth subsystem support → <*>L2CAP protocol support (CONFIG_BT_L2CAP)

Device Drivers → Networking support → Bluetooth subsystem support → <*>L2CAP protocol support (CONFIG_BT_L2CAP)

Device Drivers → Networking support → Bluetooth subsystem support → <*>SCO links support (CONFIG_BT_SCO)

Device Drivers → Networking support → Bluetooth subsystem support → <*>RFCOMM protocol support (CONFIG_BT_RFCOMM)

Device Drivers → Networking support → Bluetooth subsystem support → [*]RFCOMM TTY support (CONFIG_BT_RFCOMM_TTY)

Device Drivers → Networking support → Bluetooth subsystem support → <*>BNEP protocol support (CONFIG_BT_BNEP)

Device Drivers → Networking support → Bluetooth subsystem support → <*>HID protocol support (CONFIG_BT_HID)

Device Drivers → Networking support → Bluetooth subsystem support → <*>RFCOMM protocol support (CONFIG_BT_RFCOMM)

Device Drivers → Networking support → Bluetooth subsystem support → Bluetooth device drivers → <M>HCI USB driver (CONFIG_BT_HCIUSB)

Device Drivers → Networking support → Bluetooth subsystem support → Bluetooth device drivers → [*]SCO (voice) support (CONFIG_BT_HCIUSB_SCO)

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.

Make sure that the according modules are loaded:

# modprobe uhci_hcd ; modprobe ehci_hcd

Serial connection over Bluetooth

One of the applications you might want to connect your phone for is to use GPRS or 3G (UMTS) for connecting to the internet. A lot of phones do this through using AT-commands on a serial over Bluetooth connection.

By configuring /etc/bluetooth/rfcomm.conf correctly, you'll get a device /dev/rfcomm0.

Eventually one could use the command:

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

The hardware address should be replaced with that of your phone. If you don't know the hardware address of your phone yet, you can get it by running:

# hcitool scan

The last parameter ('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. You will have to experiment to find the right one for your phone setup; for T-Mobile GSM/GPRS carrier in USA this is channel 1.

NOTE!

By experimenting, the bluetooth stack on the cellphone may crash. Reboot it if that happens.

Now /dev/rfcomm0 exists.

At this point you can use an automatic dialing utility such as wvdial, editing the config file to point to the modem at /dev/rfcomm0, and everything should work just like a land line!

You may directly access the modem (i.e. by using minicom:)

$ minicom -s

set the serial device to be /dev/rfcomm0, choose '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.

To configure pppd create /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

Furthermore, you need a simple chat script. Create /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#'
'~--' 

Run pppd with:

$ pppd call nokia

This should establish the internet connection.

NOTE!

Different network operators may require different call strings. For many carriers (including T-Mobile USA) "*99#" works without additional parameters.

For editing phonebook / ringtones / etc., the gammu utils (http://www.gamu.net) has been reported to work well, but this appears to be primarily for Nokia phones.

File Transfer

File transfers are accomplished through OBEX transfer, which I believe is basically an FTP over bluetooth connection. Once you have bonded with your phone (yes, I know you love your sexy RAZR, but here I mean paired it with your laptop via bluetooth), you can easily use "obexftp" to transfer files. As an example,

obexftp -b 00:01:02:03:04:05 -l

will list the root directory of the phone with bluetooth address 00:01:02:03:04:05. Refer to the man page for more of the unique commands. What a wonderful interface! Unfortunately there doesn't seem to be a way to get a standard 'ftp' session using familiar commands (e.g. 'mget').

For a more user-friendly experience, you can use the kde tools, just launch

kbtobexclient

for a file browser. In the Location: option put

obex://[00:01:02:03:04:05]

to list the files. Note that the brackets *are* necessary. From there, you can list directories easily and batch download files.

External Links

• http://gagravarr.org/series-60/
• http://www.polycon.fi/~laa/biblo/linux_gprs.html
• Guide on how to set up Bluetooth in Gentoo