Disabling echo cancellation by software

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Asterisk Users 1 Comment

Dear, I have Asterisk 1.6 with an E1 Digium card with echo
cancellation module. So I need to use just the echo cancellation by
hardware and disable the echo cancellation by software. I use DAHDI
for my telephony hardware.

If the lines involved with echo cancel are:

In /etc/dahdi/system.conf:


In /etc/asterisk/chan_dahdi.conf:


What lines do I have to comment or to change the value if I want to
disable echo cancellation by software ???

Thanks a lot,


One thought on - Disabling echo cancellation by software

  • With all current releases of DAHDI if a span has a hardware echocanceler
    available, it will be used regardless of the settings in

    You can disable the hardware echocan in the wcte12xp and wct4xxp drivers by
    setting the vpmsupport module parameter to 0 when you load the driver. You
    do this from the command line (for the wct4xxp driver in these examples) with
    ‘modprobe wct4xxp vpmsupport=0’ or set ‘options wct4xxp vpmsupport=0’ in
    /etc/modprobe.d/dahdi.conf in order for it to take effect each time the driver
    is loaded.

    The v2.5.0 version of DAHDI, which is not yet released, will require that
    hardware echocan be set in /etc/dahdi/system.conf for each channel. This will
    allow a span to use a combination of software and hardware echo cancelers in
    addition to providing a way to disable the hardware echo canceler without
    reloading the drivers. Support for this feature is already committed to the
    trunk of DAHDI Linux.

    If you do check out the trunk, and want to use the hardware
    echocan, be sure to set the echocanceller line in /etc/dahdi/system.conf to
    ‘hwec’ for each channel. dahdi_genconf does not yet setup the hwec by default
    on the spans that have it available but it will before the 2.5.0 release.