Crackling noise during calls to analog lines (OpenVox A400P)

Hi,

I wish to thank you for your help, it was actually a problem with the linux kernel.
I reinstalled it without any options and started to install all options one by one. It wasn't smp or xen, but I noticed a change in the sound quality by modifying the timer frequency settings.
I don't exactly know why, but with a basic debian kernel (2.6.18 ) and the timer frequency set at 1000Hz (instead of 250Hz), it works finer.
I also changed the DSL micro filter to improve the quality of the comms.

I'm a bit perplex about all that, but thanks anyway for your help and advice.


Best regards
Sebastien Leclere


MiaoLin wrote:
> Hi:
>
> Because you are using a fairly new version, so I think it might be a
> software compatibility issue:
>
> My suggestion is:
>
> 1. try another version of zaptel, or another version of asterisk, for
> example: zaptel 1.2.xx + asterisk 1.4.x, or asterisk 1.2.xx + zaptel
> 1.4.x
>
> 2. try to close smp ( use only one cpu)
>
> 3. try to use another version linux kernel.
>
> Seems that the h/w do not have issue,
>
> I also compared the newest wctdm.c and 1.2.x , no much different. It
> also prove that the issue should be caused by linux core and newest
> zaptel.c
>
> Best wishes,
> MiaoLin.
>
>
>
>

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邮件原件

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> 发件人: Sebastien Leclere [This email address is being protected from spambots. You need JavaScript enabled to view it.]
> 发送时间: 2007年4月18日 16:52
> 收件人: This email address is being protected from spambots. You need JavaScript enabled to view it.
> 主题: Crackling noise during calls to analog lines (OpenVox A400P)
>
> Hi, I'm using Debian/Linux 4.0 (etch), kernel 2.6.18 (with SMP + Xen),
> Asterisk 1.4.2, Zaptel 1.4.1.
>
> Recently, I noticed on incoming and outgoing calls to my analog lines
> (A400P) very disturbing crackling noise, during dialing tones and calls.
> The problem repeated, using SIP phones (virtual or not, handless or
> not, on speaker or not).
>
> I'm using a OpenVox A400P card with 2 FXO modules, both linked with 2
> different analog lines (spanish telefonica lines). I tried to pass the
> calls without asterisk (directly linking an analog phone to the analog
> line, and there... no problem, that should be an asterisk/zaptel/phone
> card problem).
>
> The problem occured only since I updated my system to zaptel 1.4.1.
>
> I tried to active/desactive all echo cancellation features, that
> doesn't change anything. Same for the RX/TX gain in ztmonitor, and i
> still couldn't solve the problem. The most I can do is to cancel the
> echo quite well, but the crackling noise don't leave with the echo.
>
> The WCTDM opermode is well fixed to the right country (SPAIN in that
> case), but the problem is still there if i change the opermode to none
> or us.
> Same for the progzone in zapata.conf (set to es).
>
> I also checked for possible interrupt problems in /proc/interrupts,
> and the wctdm driver is not sharing interrupt with anything.
>
> I cannot see any other test I can do to find the source of this noise.
> Nothing strange on logs or asterisk console (no interesting debugs to
> attach here).
>
> Could it be a timing problem? Any suggestions?
>
> Thanks a lot in advance.
>
> Sebastien Leclere
>
>
>