Echo Problem

Discussion in 'General' started by is99, May 16, 2010.

  1. is99

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    I have a Digium PRI card with ccho cancel module installed on it.
    I have a huge Echo Problems during calls.


    I see this in dmseg

    wcte12xp: VPM present and operational (Firmware version 117)

    however when I go to /etc/dahdi/system.conf it shows:

    echocanceller=oslec,1-15,17-31



    dahdi_cfg -vvv shows this:

    DAHDI Tools Version - 2.2.0

    DAHDI Version: 2.2.0.2
    Echo Canceller(s): OSLEC
    Configuration
    ======================

    SPAN 1: CCS/HDB3 Build-out: 0 db (CSU)/0-133 feet (DSX-1)

    Channel map:

    Channel 01: Clear channel (Default) (Echo Canceler: oslec) (Slaves: 01)
    Channel 02: Clear channel (Default) (Echo Canceler: oslec) (Slaves: 02)


    So it looks like I'm not using Hardware Echo ?
     
  2. milauria

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    If it is a hardware echo canceller I don't think that software settings in dahdi.conf really matter, did you tried to refer to the DIGIUM instructions first ?
     
  3. jgutierrez

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    What I would do is the following:
    1. Check /etc/asterisk/chan_dahdi.conf and make sure that rxgain and txgain are equale to 0.0
    2. Make sure that the echo issue are not caused by the phones or softphones, call into extensions, and see what happens
    3. Execute:
    amportal stop
    service asterisk stop (until it fails)
    fxotune -i 4
    .... (wait until it finishes)
    amportal start
    4. Test again if you have echo issue
     
  4. is99

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    fxotune -i 4 Returns me these errors:

    Tuning module /dev/dahdi/31
    Unable to set impedance on fd 4
    Failure!
    /dev/dahdi/32 absent: No such file or directory
     
  5. jgutierrez

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    There is no problem. It just says it, because there is no module on that channel. Dont worry about, just let it finish all the channels that have an fxo module, and then execute an amportal start
     
  6. is99

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    Yes the "/dev/dahdi/32 absent: No such file or directory" etc erors I understand.

    But on all the chanels that do exist it shows:
    Tuning module /dev/dahdi/21
    Unable to set impedance on fd 4
    Failure!


    And in the end it shows:
    Unable to tune 31 devices, even though those devices are present
     
  7. dicko

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    I think you will find fxotune only works on fxo ports, (ISDN B channels aren't such a beast ), I suggest you use a milliwatt test and dahdi_monitor and play with your rx/tx gains in /etc/asterisk/chan_dahdi.conf if necessary and there is a noticable discrepancy on those levels. (I have posted here before on this subject i.e. 2-4 wire hybrids, so I know it's here somewhere)
     

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