chan_celliax:

1

• chan_celliax
• Cellphones as Asterisk GSM and SMS Channels
• (with Skype Support)?
• Astricon 2007

2
Agenda

• chan_celliax Pictures
• chan_celliax Features Overview
• Asterisk Channels How Do They Work
• chan_celliax implementation
• celliax.conf configuration file
• chan_celliax CLI commands
• chan_celliax dialplan applications
• chan_celliax dialplan (extensions.conf)?
• Celliax LiveCD
• chan_celliax hard disk installation
• AudioCables and DataCables
• Celliax troubleshooting
• Celliax TODO

3
One Picture....
4
...a thousand words
5
chan_celliax Features Overview

• Works well on Linux and Windows XP (CygWin)?
• Use Datacable to (USB) serial port and Audiocable
  to soundcard, as interface to the physical
  cellphone
• Incoming and Outgoing call to/from most popular
  (cheap) cellphones and other communication
  devices
• Outgoing SMSs (Incoming are TODO)
• Skype Client Incoming calls are passed through
  the cellphone interface (dialing a remote
  number)?
• Skype and SkypeOut Outgoing calls can be
  originated by the cellphone interface (via the
  Skype Client)?
• Cellphone phonebook and Skype Client Contacts
  import into dialplan and directory
• Directory export to cellphone phonebook (one
  click dial from the cellphone)?

6
How an Asterisk channel works

• Each channel driver implements the functions to
  be used by Asterisk (call, answer, dial, etc)?
• Into the driver, a loop thread monitors all its
  physical interfaces, accepting interface events
  (RING, DOWN, etc)?
• When a call incomes or is originated, the driver
  creates an instance that mediates between
  Asterisk and the interested interface. That
  particular interface is no more in the monitored
  pool
• When the call is finished, that interface go back
  into the monitored pool

7
Implementation 1 (monitors)?

• We need to monitor various sources of events
• serial (for datacable incoming indications)?
• skype (for Skype client incoming indications)?
• audio (for sensing a RING if we do not have
  serial indications, eg Nokia 3310, or no
  datacable)?
• We have a loop monitor thread for each kind of
  source

8
Implementation 2 audio

• Audio tends to be platform specific, CygWin has
  only a very rough OSS-like layer
• We need an audio API that allows for sharing of
  the audio interface between Skype and Celliax
• ALSA Linux only, low latency, allows sharing via
  plugin (default, dmix-dsnoop), the most difficult
  audio API
• WinMM Windows only, allows sharing, low latency
  on Windows XP, unacceptable latency on Vista
• OSS BSD and Linux, low latency, do not allows
  sharing. Only recently the commercial version was
  opensourced, it allows sharing. TODO
• CoreAudio Mac OSX, low latency, allows sharing,
  TODO
• Incoming audio is analyzed to recognize silence
  and DTMFs

9
Implementation 3 serial

• Serial interfacing is fairly portable, very well
  implemented by CygWin on Windows
• We need various types of serial signaling
• AT standard commands, for the most part of
  cellphones
• FBUS2 proprietary commands, for various Nokia
  models
• Other serial commands/signaling protocols, eg.
  for DECT modules
• Each kind of signaling has its own functions,
  over a common serial layer for physical I/O

10
Implementation 4 skype

• Without hacks, the Skype Client can have one only
  instance for computer, so one only chan_celliax
  interface can be skype enabled at this moment
• On Linux, the Skype Client API uses X11 messaging
• On Windows, the Skype Client API uses standard
  Window Messages
• For both Linux and Windows, chan_celliax creates
  a fake window with its own message loop, then
  dispatch messages to the skype monitor or to the
  appropriate interface thread
• Skype Client API is very easy, text based, but do
  not allows for audio stream I/O, we need to share
  the audio device
• Mac OSX TODO

11
celliax.conf configuration file 1

• Each section between brackets defines an
  interface, eg nicephone is the
  Celliax/nicephone
• The first interface defined in celliax.conf sets
  the defaults for all the following interfaces.
  Defaults can be overridden by each interface
• The most important KeyValue couple are
• skypeyesno this interface will interact with
  the Skype Client, if any
• control_device_protocolatfbus2no_serial...
• control_device_name/dev/ttyUSB0/dev/ttyACM0...
  
• alsa_capture_device_namedefault0plughw3...
• winmm_playback_device_name03...

12
celliax.conf configuration file 2

• Many, many, many other keyvalue couples allows
  for fine tuning of each interface
• audio fragment and buffer sizes
• serial speed
• most AT commands and indications can be specified
  to accommodate for cellphones non ETSI standard
• need_acoustic_ring can be enabled to accommodate
  for cellphones that do not give incoming RING
  serial indication, or when no datacable is used
  (eg. Nokia 3310 or a cellphone with autoanswer
  enabled)?
• dsp_silence_threshold can be set to determine how
  much noise is no more silence
• playback_boost scales up or down the audio signal

13
CLI commands 1 interface stuff

• From the Asterisk CLI console, you can give
  various commands to interact with chan_celliax
• celliax give a list of chan_celliax CLI commands
  and dialplan applications
• console shows or sets the chan_celliax interface
  on which further commands are acting upon
• dial, hangup during a call, sends DTMF to the
  interface (not to remote party) or hangup the
  call. Useful for no_serial tests without
  cellphone (only headset/mic)?
• celliax_playback_boost shows or sets the audio
  scaling
• celliax_capture_boost shows or sets the audio
  scaling
• celliax_alsa_period shows or sets the ALSA
  fragment and buffer size

14
CLI commands 2 directory stuff

• celliax_dir_import imports entries into the
  celliax_dir.conf file and adds them as extensions
  to the dialplan, in the celliaxdir-default
  context
• addreplace appends to the existing file or
  substitute it
• fromskypefromcell the entries are sourced
  from the Skype Client Contact list or from the
  cellphone phonebook (soon also from csv files)?
• celliax_dir_export exports the extensions from
  the celliax_dir.conf into the cellphone
  phonebook, prefixing each one with the interface
  cellphonenumber and a pause, so you can one-click
  dial from the remote cellphone
• tocell write only to cellphone phonebook now
  (soon also to csv files)?
• cellphonenumber the number at which the
  interface answers

15
Applications 1 - celliax_directory

• Celliax_Directory(vmcontextdialcontextf)?
• it works very similar to the Asterisk standard
  directory application, but it reads the specific
  celliax_dir.conf that is populated by the
  celliax_import CLI command with entries from the
  Skype Client Contacts list and/or from the
  cellphone phonebook
• it asks you to digit the first three letter of
  the person you want to call, tells you who it is,
  and if you confirm, make the call (through Skype
  or whatever) to him
• vmcontext is the celliax_dir.conf section we want
  to use
• dialcontext is the context used to make calls
• f is for use the first name (as opposed to last
  name) of the directory entry

16
Applications 2 - celliax_sendsms

• Celliax_SendSMS(interfaceremote_number,text)?
• Sends an SMS to the cellphone at remote_number
  with content text, using the given interface
• interface is the name of the chan_celliax
  interface we want to use for sending the SMS, eg.
  nicephone
• remote_number is the number of the cellphone to
  which we want to send the SMS to
• text is the content of the SMS, all standard
  dialplan escaping rules apply, eg DATETIME
  "This a SMS test\, we\'re testing\, yes\, we\'re
  testing..."

17
Applications 3 - celliax2skype

• Celliax2Skype(skypenameskypecontactskypeoutnumbe
  r)?
• During an incoming chan_celliax call, make a
  Skype call to the given remote party and let the
  chan_celliax interface share the audio path with
  the Skype Client (so, the incoming chan_celliax
  call is bridged to the outgoing Skype call)?
• skypename is a valid skype name, eg echo123
• skypecontact is an entry in the Skype Client
  Contacts list
• skypeoutnumber is a valid number for SkypeOut
  calls

18
Applications 4 - skype2celliax

• Skype2Celliax(remotenumber)?
• When a Skype call is incoming into the PC running
  Asterisk, if there is a chan_celliax interface
  Skype-enabled that is not yet into a call, a call
  is initiated into the skype context, where a
  skype2celliax extension is lurking.
• The skype2celliax extension makes a call to the
  remote_number through the chan_celliax interface
  and let the chan_celliax interface share the
  audio path with the Skype Client (so, the
  outgoing chan_celliax call is bridged to the
  incoming Skype call)?
• remote_number is the number to be called when a
  Skype call is incoming

19
Dialplan (extensions.conf)?

• Contexts
• celliaxdir-default
• is created at chan_celliax startup and with
  celliax_dir_import
• contains the extensions from the celliax_dir.conf
• if included in the default incoming call context,
  allows one-click dial to its extensions from
  cellphones which phonebooks has been populated by
  celliax_dir_export
• skype
• the context where incoming Skype calls arrives,
  see skype2celliax
• Dial
• standard Asterisk usage, eg dial(nicephone333444
  5)?
• celliax_directory, celliax_sendsms,
  celliax2skype, skype2celliax
• see before, Applications

20
LiveCD 1 - contents

• Knoppix based livecd, autobooting, with Skype,
  Asterisk, chan_celliax, and configuration
  utilities
• ISO image of AstLinux based livecd, to be burned
• USB self contained distro for Windows XP
• Asterisk with chan_celliax distro for Windows XP
• Drivers for datacables on Windows XP (Linux do
  not need them)?

21
LiveCD 2 - usage

• Knoppix
• setup skype first
• then setup celliax
• save configuration on USB pendrive
• reboot
• AstLinux
• burn and go
• USB Windows XP
• copy on USB pendrive and go
• Windows XP hard disk installation
• install basic Cygwin some libraries
• unpack asterisk.tgz in /usr/local and go

22
Installation 1 chan_celliax only

• Linux
• If you have previously installed Asterisk from
  sources, or from your distro package (with the
  latter you need the asterisk-devel package too)
• download the celliax_stuff.tgz
• go into the celliax_stuff/build directory
• edit the Makefile
• compile (need ALSA and libX11 devel packages)?
• copy chan_celliax.so in the Asterisk modules
  directory
• copy celliax.conf in the Asterisk configuration
  directory
• edit celliax.conf or use the celliax_config
  utility

23
Installation 2 Asterisk too

• Linux and Windows XP
• If you want an installation similar to the
  LiveCD
• you'll need all the stuff needed for Asterisk
  compilation plus ALSA and libX11 development
  packages
• checkout from svn the tag you are interested in,
  eg svn checkout http//www.celliax.org8081/svn
  /celliax/tags/celliax_livecd_beta01RC1/
• go into the asterisk-1.2.XX directory
• make make install make samples
• all will be installed under /usr/local/asterisk
• copy the contents of newconfigs directory into
  /usr/local/asterisk/etc/asterisk/
• copy the contents of sh directory into
  /usr/local/asterisk/usr/sbin/
• configure and launch with /usr/local/asterisk/usr/
  sbin/celliax

24
Installation 3 on TrixBox

• TrixBox 2.2.X series is based on Centos 4, that
  has very very old ALSA and whiptail versions, and
  uses its own script to start Asterisk, configure
  permissions, etc
• We need to update the ALSA version, install ALSA
  and libX11 devel packages, install a recent
  dialog version as alternative to whiptail,
  compile chan_celliax and modify TrixBox scripts
• A very detailed and easy step by step How To
  TrixBox is available on www.celliax.org

25
AudioCables

• We need an audiocable between the cellphones we
  use as celliax interfaces and the soundcards of
  the PC running Asterisk
• You can buy it or build it (little soldering
  needed)?
• For cellphones using standard 3pole 2.5mm
  handsfree jack you can start from a cheap headset
  cut it before the microphone and solder two 3pole
  3.5mm jacks
• For Nokias using 4pole 2.5mm handsfree jack more
  work is needed
• electrical schemas are availables at
  www.celliax.org
• Professionally manufactured audiocables are
  available at www.celliax.org

26
DataCables

• It's much better to have a datacable between the
  cellphones we use as interfaces and the serial
  ports (or USB) of the PC running Asterisk
• chan_celliax can work without datacable, but it
  cannot originate calls, will have no information
  at all on the incoming calls (autoanswered by the
  cellphone) and will rely on a period of silence
  to notice a remote hangup
• Most cellphones has datacables available, at
  least aftermarket (notably Nokia models)?
• Datacables for the cellphones most used with
  chan_celliax are available from www.celliax.org

27
Troubleshooting 1 - Audio

• Audio Mixer values setup
• You need working audio incoming from microphone
  (capture-recording) and outgoing from
  speakers-headset (playback)?
• Check that the Microphone is muted for playback
  (or it will loop back to you)?
• Check that the Microphone is selected for capture
• Check if your microphone needs an audio boost
  from the mixer
• Eventually, play with scaling up or down audio
  capture and playback signals in the config file
  or through CLI commands

28
Troubleshooting 2 - serial

• Check that the controldev_protocol for this
  interface in the celliax.conf file is correct
• Check that the control_device_name for this
  interface in the celliax.conf config file is
  correct
• Check that the serial speed for this interface in
  the celliax.conf config file is supported by the
  cellphone (FBUS2 always uses 115200)?
• Check that the device has been correctly created
  by the operating system (on Linux you can use
  dmesg, on Windows use controlpanel for ports
  and modems)?

29
Troubleshooting 3 - permissions

• Various Linux distro do not allows general
  permissions to write and read the sound and
  serial devices
• Often those permissions are reset at each reboot
• Check that the user Asterisk is running as has
  the needed permissions
• Make a startup script (an rc.local, or an
  Asterisk launching script) that gives to the
  Asterisk user all the necessary permission, eg
• chown -R asterisk.asterisk /dev/snd
• See the Trixbox How To on www.celliax.org

30
Troubleshooting 4 debug logging

• Chan_celliax has very fine grained debug logging
  messages, much more you can stare at
• in the config file, activate the desired
  debug_yes for each category you want messages
  about (skype, at commands, pbx functions,
  interface state, locking, etc)?
• then activate debug in Asterisk itself, via CLI
  command or at startup (set debug 100 or with
  the -ddddd startup option)?
• do not forget to allow debug messages in console
  or in the logfiles, edit logger.conf for this!

31
TODO

• Mac OSX
• Incoming SMS management
• CSV files import export to directory
• OSS audio
• Test, test, test
• How to contribute
• checkout the latest sources from svn trunk
• send patches to the celliax-dev mailing list
• ask for a committing svn account

32
Thank you for your attention!

• for more info www.celliax.org
• Giovanni Maruzzelli
• gmaruzz_at_celliax.org