Noise in caller handset when dialing out (with dahdi 2.6.0)

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Asterisk Users 4 Comments


On a brand new system, I met an issue I’ve never met before.

My setup is :
debian 6.0.3
dahdi 2.6.0
libpri 1.4.12
TE420FB (with hardware EC)

This is the very first time I’m using Freepbx and the whole
configuration was first generated by a “make samples” command.

When a SIP hardphone dials another SIP hardphone, everything is OK.
When the same SIP hardphone dials an external number, there is a quite
loud noise that can be heard within the handset from the moment the
digit sequence have been sent to the moment any party hangs up. The
other party doesn’t hear this noise.
(It’s not easy for me to describe this noise)

I don’t have any idea of where to look at.
What would you suggest or recommend ?


4 thoughts on - Noise in caller handset when dialing out (with dahdi 2.6.0)

  • At a guess this sounds like a possible mismatch between A-law and
    mu-law companding. When this happens, you hear something like static
    only when someone is speaking.


  • Hi Olivier, I just received another report of this in the morning
    and was able to reproduce it. I’ll create a JIRA issue here shortly
    with a patch and reply to this thread with that patch.

    Sorry about the trouble,

  • Hi,

    1. This patch didn’t correct the issue but I’m far from certain that I
    correctly applied the patch.
    2. I took the Hardware Echocan module off my board and it seems to
    correct the issue.

    I’ll dig deeper to check if I correctly applied the patch and both
    report here and in DAHLIN-275 ticket.

    2012/1/9, Shaun Ruffell :