Bluetooth-alsa Project   This project provides a way to use a bluetooth headset with Linux. We   do this currently by making an alsa kernel driver which uses bluez to   reach the headset. It works well enough now to get voice-quality audio   to and from most headsets. We've had success with:     * Ericsson HBH-60     * Ericsson HBH-35     * BlueTrek 1     * Jabra BT200, BT250     * Siemens HHB-600     * Logitech HS01 (has a noisy microphone?)     * Motorola HS801 (volume must be changed from headset?)     * Plantronics M2500     * Logitech Mobile F-0179A     * Bluetake iPhono BT420 (using either sco or a2dp)     * Motorola HS810/HS850 (may work "better" if you manually specify       the handsfree channel, 8)     * Canyon CN-BTH1 (must click headset's volume-up button after each       connection)   We currently don't have any code to make the connection to an audio   gateway (typically a cellphone). There's a [1]project associated with   asterisk and a [2]standalone app for using a cellphone.  Features   We have code to make a headset connection (using the btsco daemon) to   send audio through the alsa system and we have separate code to send   stereo audio to the a2dp device using a userspace program (a2play).   Only a couple of headsets can accept stereo audio so try the btsco   stuff first.  Build    1. Install or update the required packages:          + automake-1.7          + libao-dev (known as libao-devel on rpm systems)          + libbluetooth-dev (aka libbluetooth-devel or bluetooth-devel)          + libasound2-dev (aka alsa-devel)          + a recent 2.6 kernel with *integrated* alsa enabled (it won't            work with the "standalone" alsa drivers that are a separate            download from the kernel)    2. Check btsco out from cvs:        cvs -d:pserver:anonymous@cvs.sf.net:/cvsroot/bluetooth-alsa login        cvs -d:pserver:anonymous@cvs.sf.net:/cvsroot/bluetooth-alsa co btsco    3. Compile:        ./bootstrap        ./configure        make        make install        make maintainer-clean    4. For SCO (two-way voice quality audio) you need a kernel with the       emu10k1 driver selected (this is one of the drivers that forces       the inclusion of the implementation of "snd_hwdep_new"). Build the       kernel module:        cd kernel        make        make install        make clean  Using SCO audio    1. insert the module (or better, set up the alsa configuration to       load it)        modprobe snd_bt_sco    2. stop the esound controller if it's running via        esdctl stop    3. turn on the headset (you may need to prepare the headset to be       paired the computer, usually by turning on the headset and holding       the on button until it beeps)    4. run the handler in the foreground and let it keep running (enter       the passkey if it's the first time 'round)        btsco bdaddress    5. click the connect button on your headset    6. send and receive audio from the headset (usually using /dev/dsp1)       or via the alsa device with something like        aplay -B 1000000 -D plughw:Headset sound.wav  Stereo (A2DP) Streaming   A2DP provides a way to send stereo high-quality audio to some of the   newer headsets. On all the headsets I've seen so far, this is one-way   audio, so if you were expecting to get something like a gaming headset   (talking to other players, getting stereo sound back from the game),   you should wait for the next generation of headsets to get 2-way A2DP.   Right now A2DP is done in the classic Unix tradition by a series of   pipes. From the btsco directory after a successful make:        mpg123 --au - file.mp3 | sbc/sbcenc - | ./a2play bdaddr   Where you replace file.mp3 with a good mp3 file and bdaddr with the   address of your headset. If you have trouble with using a2play, let us   know on the mailing list if this works for you instead:        mpg123 --au - file.mp3 | sbc/sbcenc - | ./sbc/rcplay bdaddr -   You can send live audio from line-in etc using a command like:        arecord -c 2 -r 44100 -f S16_BE -t au /dev/stdout | ./sbc/sbcenc - | ./a2play bdaddr   Don't be surprised to get a delay. It's probably under 500ms but not   much under that.  A2DP userspace plugin   We're not being totally true to the project name at this point...   there's not an ALSA connection yet with hifi. I think this will make   the question of the next step even more poignant.   If you want to experiment with the early alsa userspace plugin work,   go to the directory 'bt' in the cvs archive (yeah, great name but   renames are a pain in cvs :) and have a look at the BUILD docs there.  Links     * [3]Bug list at sourceforge     * [4]Bluez main page  Discussion   This code is all experimental, so the best place to talk about it and   submit changes is on the bluez-devel mailing list.   If things aren't working as you expect, some of the things that can   help us track it down are:     * Manufacturer and model of headset and bluetooth adapter     * Output from hciconfig -a     * Output from hciconfig hci0 revision       Run hciconfig as root; if it says "SCO mapping: PCM" then you need       a different bluetooth adapter     * Output from hcitool info bdaddr where bdaddr is the headset's       address     * Output from hcidump -X while running btsco or a2play if       appropriate     * The output btsco -v or a2play prints to the screen     * Your kernel version and bluez userland versions or distro     * Result when trying it with a recent kernel if possible (eg       2.6.10-mh2)     * If you have a headset that can do a2dp, try both btsco and a2play       (the significance is that the latter does not use SCO)     * If you can try another bluetooth adapter or headset, let us know       if that helps (the adapters are cheap now, eh? :)  Credits   Some instrumental people in this effort:     * [5]Jonathan Paisley (retired from the project) started it up and       wrote much of what we have now     * [6]Niko Berger brought the patches forward to 2.6.7 and 2.6.8     * [7]Lars Grunewaldt [largegreenwood (at) users.sourceforge.net]       added some stuff to the userspace daemon and is working on mode       change hooks     * [8]Marcel Holtmann has always been the key developer for bluez and       has recently jumped in and helped a lot with our project       specifically     * Henryk Ploetz donated SBC manipulation code and brings a       significant understanding of this codec     * [9]Brad Midgley is doing documentation, A2DP protocols, vendor       relations, and project coordination     * Fredrik Tolf has been fixing up daemon/userspace interactions   Back to the [10]bluetooth-alsa project pages     _________________________________________________________________   [11]SourceForge.net Logo References   1. http://www.crazygreek.co.uk/content/chan_bluetooth   2. http://www.soft.uni-linz.ac.at/_wiki/tiki-index.php?page=ProjectBluezHandsfree   3. http://sourceforge.net/tracker/?group_id=116589&atid=678258   4. http://www.bluez.org/   5. http://www.dcs.gla.ac.uk/~jp   6. http://www.gargan.org/   7. http://www.dark-reality.de/   8. http://www.holtmann.org/linux/bluetooth/   9. http://www.xmission.com/~bmidgley/  10. http://sourceforge.net/projects/bluetooth-alsa/  11. http://sourceforge.net/