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Asterisk GSM

     

     

    Overview

     

    Asterisk uses the Libwat to interface with the Sangoma W400 GSM cards.

     

    Asterisk Libwat Architecture.png

     Installation

    Download the following System requirements
    -> Prerequisites
          * Note: if you do not install the above requirements the installation will fail

     

    Dahdi Installation


    1. Download the latest Dahdi sources from asterisk.org:
         example:

     wget http://downloads.asterisk.org/pub/telephony/dahdi-linux-complete/releases/dahdi-linux-complete-2.5.0.2.+2.5.0.2.tar.gz

    2. Untar and install dahdi

    tar xfz dahdi-linux-complete-2.5.0.2+2.5.0.2.tar.gz
    cd dahdi-linux-complete-2.5.0.2+2.5.0.2
    make && make install

     

     

    Wanpipe Installation

    Installation

     

    LibWAT Installation

    1. Download the latest LibWAT:

    wget ftp://ftp.sangoma.com/linux/libwat/libwat-1.0-current.tgz

     

    2. Untar & Compile & Install

    tar xfz libwat-1.0-current.tgz
    cd libwat-X.X.X/build
    cmake ..
    make
    make install


    Asterisk LibWAT Patching

    Currently, libwat requires a patched version of Asterisk to work. Libwat Asterisk patches can be found in the libwat-X.X.X/asterisk directory.

    Autoconf

    You will need autoconf 2.60 or later to be able to patch Asterisk.

    wget http://ftp.gnu.org/gnu/autoconf/autoconf-2.68.tar.gz
    tar xfz autoconf autoconf-2.68.tar.gz
    ./configure
    make
    make install

     

    Copy patches to asterisk source directory. Make sure to use the patch version that matches your version of asterisk:

    cd libwat-1.X.X/asterisk
    cp asterisk-<your specific asterisk patch> /usr/src/asterisk-<verison>


    To patch your Asterisk Installation:

    cd asterisk-<version>
    patch -p 1 < asterisk-<version>.patch


    Re-configure and re-compile your Asterisk:

    ./bootstrap
    ./configure
    make clean
    make
    make install

     

     

    Configuration


    Use the wancfg_dahdi script to generate your configuration files

    wancfg_dahdi

     

    Asterisk GSM Advanced Configuration options

    Sending and Receiving SMS with Asterisk

    1. Sending/Receiving SMS using Asterisk CLI
    2. Sending/Receiving SMS using Asterisk Management Interface

    Sending SMS using Asterisk CLI

    Syntax:

    wat send sms <span> <number> <message>


    Example:

    CLI> wat send sms 1 6474024628 "Hello World"



    Receiving SMS using Asterisk CLI

    When a SMS is received, it will printed in the Asterisk CLI and the logs.

    -- Span 1: SMS received Hello World

     

     

    Debugging

    It is recommended to enable Asterisk full debugging while the LibWAT library is still in beta phase to facilitate debugging.

    Instructions on how to enable Asterisk Full Debug Logging


    Enable debug configuration in chan_dahdi.conf

    In chan_dahdi.conf in the Channel section create a variable called:

    wat_debug=

    Below are the possible options to use for wat_debug:

    all

    uart_raw

    uart_dump
    call_state
    span_state
    at_parse
    at_handle
    sms_encode
    sms_decode

    For example: wat_debug=all

    any combination of the above separated by commas will work.

    Most of the time I'd stick to "all" when debugging a problem and only use the others if you've been asked to.

     

     

     

     You can also enable UART (serial interface) debugging to see which AT commands are sent and received at the driver level:

    wanpipemon -i w1g1 -c gude

     

    All UART communications will be dumped to the driver logs (ie: /var/log/messages)

    To disable UART debugging:

    wanpipemon -i w1g1 -c gudd

    (gude - GSM uart debug enable)
    (gudd - GSM uart debug disable) 

    Troubleshooting


    1. Confirm that SIM cards are inserted

    wanrouter status

    Devices currently active:
    wanpipe1 wanpipe2 wanpipe3 wanpipe4


    Wanrouter Status:

    Device name | Protocol | Station | Status | Wanpipe | Lapb | X25 Link | X25 Svc | Dsp |
    wanpipe1 | AFT GSM | N/A | Connected | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
    wanpipe2 | AFT GSM | N/A | Disconnected | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
    wanpipe3 | AFT GSM | N/A | Disconnected | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
    wanpipe4 | AFT GSM | N/A | Disconnected | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |

     

    GSM modules that do not have a SIM card connected will have status: Disconnected 

     2. Checking network registration

    From the Asterisk CLI:

    CLI> wat show spans

     

    WAT span 1: Up ("+16472673394")
    WAT span 2: Down
    WAT span 3: Down
    WAT span 4: Down

    Devices that have registered to the network successfully, will have status: Up. If the subscriber number (own number) is available, it will be displayed beside that span ("+16472673394" in our case). 

     

    3. Checking Signal Quality 

    From the Asterisk CLI:

    CLI> wat show span 1

     


    WAT span 1: Up
    Status: Registered Home
    Operator: "ROGERS"

    Signal strength: (-77)dBm
    Signal BER: less than 0.2%

    Subscriber: "+16472673394" type:1 plan:1 <"TELEPHONE">
    IMSI: 302720407395781

    Manufacturer Name: GC864-QUAD-V2
    Manufacturer ID: Telit
    Revision ID: 10.00.053
    Serial Number: 359551031929812

     


    1. It is recommended to have a signal strength higher that (-80) dBM (a value between -50 dBM and -80 dBM) to avoid dropped calls.
    2. Having a high Signal BER (Bit Error Rate) may affect audio quality.
    3. The first time the GSM modules are started in a location, it may take up to 6 minutes for a GSM signal to be detected. This is because the GSM chip is iterating through each of the 4 GSM bands to search for a signal. Once a signal is detected, the band is memorized, and subsequent starts will take only  a couple seconds.

     

    3. Enable Asterisk command line debugging

     

    Aside from the driver debugging of the serial line (which sends and receives AT commands, responses and notifications), Asterisk can also print AT debugging information to the screen, which is easier to correlate to call events within Asterisk.

    If you have the latest libwat release + Asterisk patch, there is a way to enable debugging from the command line:

    CLI> core set verbose 3
    CLI> core set debug 3
    CLI> wat debug all

     

    Even when wat debugging is enabled, you still have to enable regular Asterisk debugging settings:

     /etc/asterisk/logger.conf

    [logfiles]

    sangoma_gsm => notice,warning,error,debug,verbose,dtmf,fax

     

    When changing this file you must either restart asterisk or execute "logger reload". Note that if you restart Asterisk the debugging options (verbose, debug, wat all) enabled thru the command line will be lost. Therefore you want to do the logger.conf changes first.

     

    Please verify the have latest libwat and Asterisk patch, if they do not have it the command "wat debug all" won't be available.