[Asterisk-Users] Re: Asterisk Crackly Bad quality

[David Uzzell]

Keith O'Brien wrote:
> Thanks. On a related note.  The problem that I am troubleshooting has to do
> with an IAX connection to TELIAX.   Outgoing calls are perfect.  When I have
> incoming calls they are very crackly and break up.   I have checked the
> jitter buffer and it is not overrunning so it doesn't appear to be a jitter
> or packet loss problem.
> 
> I am beginning to suspect that since I don't have a ZAPtel card in my
> machine, * is losing sync with the incoming stream.  From what I understand,
> if there isn't a zap timing source * uses the incoming data stream to derive
> timing.  

I have been watching the to and fro of this over the last day or so and 
being a fairly newbie myself, Just looking plainly at what you have 
running, You have a SMP kernel running on a Dual Capable server but with 
only 1 cpu.

Why Don't you run a NONE SMP kernel, one which would be suited to the 
fact that you only have one CPU in the server.

Then the other thing if mem serves me you are running 2.6 kernel so why 
not run ztdummy? With the 2.6 kernel this does not require any 
specialist Hardware or anything!


I have * running on Mandrake 10.1 and I to had similar problems in the 
begging but as soon as I had ztdummy configured correctly everything 
seemed to just fall into place and work with IAX and *, not that I have 
got a perfect dialplan as that confuse's me but hey thats another subject.

David



> 
> Since the incoming stream is using VAD, my assumption is that it is losing
> the timing during the pauses in the speech.   Does anyone know of a way to
> just turn off VAD in *?   This would have multiple benefits (if you have the
> bandwidth).   Turning off VAD will improve voice quality by eliminating and
> front end clipping during talk spurts and I am assuming will also minimize
> the impact of not having a ZAP timing source.
> 
> Is there a way to disable VAD in *?
> 
> Thanks again.
> 
> -----Original Message-----
> From: Martin List-Petersen [mailto:martin+asterisk at list-petersen.net] 
> Sent: Saturday, December 18, 2004 8:20 PM
> To: Keith O'Brien
> Cc: asterisk-users at lists.digium.com
> Subject: Re: [Asterisk-Users] Re: Asterisk Crackly Bad quality
> 
> Citat Keith O'Brien <keitheobrien at yahoo.com>:
> 
> 
>>The URL you are looking for is:
>>
>>http://www.voip-info.org/wiki-Asterisk+timer
>>
>>Thanks.  After reading through the notes I checked my server (Dell 1750)
>>and
>>noted that it uses a USB OHCI interface so the first option doesn't appear
>>to be an option.   Also it indicates that the second option of using
> 
> zaprtc
> 
>><http://www.voip-info.org/wiki-Asterisk+zaprtc>  won't work on SMP
> 
> systems.
> 
>>The 1750 is a SMP system and I am running a 2.4 SMP kernel but do not
>>actually have a second processor installed.   Can I still use zaprtc with
> 
> a
> 
>>SMP kernel if the second processor isn't actually installed??
>>
> 
> 
> zaprtc should work indeed if you only have one CPU in the system.
> 
> Slán Leat,
> Martin List-Petersen
> Dublin, Eire
> (contact info ==> http://www.marlow.dk)
> --
> We Klingons believe as you do -- the sick should die.  Only the strong
> should live.
> 		-- Kras, "Friday's Child", stardate 3497.2
> 
> 
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