[Asterisk-Users] Clicks in audio with TE100P PRI

[Kris Boutilier]

> -----Original Message-----
> From: asterisk-users-bounces at lists.digium.com
> [mailto:asterisk-users-bounces at lists.digium.com]On Behalf Of Alejandro G
> Sent: Friday, June 10, 2005 8:12 AM
> To: asterisk-users at lists.digium.com
> Subject: [Asterisk-Users] Clicks in audio with TE100P PRI
> 
> 
> 
> It seems that configuring span=1,1,0,ccs,hdb3 and changing 
> jitterbuffer=16 resolves or masks the issue. What I will do now is reduce 
> again jitterbuffer to default to see what happens.
> 

Your issue is very likely the size of the zaptel jitterbuffers setting. If the zaptel driver is not immediately available to accept a frame of data it places it in an internal queue of pending writes. If that queue is full then the write is refused by the zaptel layer and then silently discarded by chan_zap causing a gap in the audio once it is played out of the zaptel card. If you crank up the debug level you will probably see 'Write returned -1...' (aka. EAGAIN) debugs that mostly correlate to the pops and clicks. Note that the zaptel driver legitimatly (if perhaps not appropriately) also refuses data when the channel is muted, such as during DTMF generation and at other times, so not _all_ EAGAIN debugs are a sign of problems.
	
There is more background on my experience with the T100P pop&click issue in http://lists.digium.com/pipermail/asterisk-dev/2005-May/012432.html

Hope that helps.

Kris Boutilier
Information Systems Coordinator
Sunshine Coast Regional District