[asterisk-users] "clicking" sound with alaw codec

[Patrick Lists]

On 01/24/2013 09:44 PM, Richard Kenner wrote:
[snip]
> When I use alaw, the path from Asterisk to the Alcatel is completely
> clean, but the other way has a set of clicks that kind of sound like
> old-fashioned audio noise.
[snip]

It's been ages since I experienced that but things to check that come to 
mind in no particular order are:

- DAHDI settings (sync source)
- Asterisk server not properly grounded
- timing is off (check logs)
- shared interrupts (make sure nic/TDM card have their own)
- jitterbuffer settings (try on/off)
- echo cancellation going bonkers (OSLEC?)
- QoS (proper priority for voice packets?)
- PCI slot (if you have a card, try changing the slot it's in)

Use Wireshark to see the difference between a good call and a bad one. 
If you see a lot of time jumps on the bad call then look at your 
network/QoS.

Regards,
Patrick