[asterisk-users] Background noise

[Philipp von Klitzing]

Hi!

> it should be some commands that can give me a better idea about the
> codecs, if anyone know them, please help! 

Use "sip show channels" and "iax show channels" and look at the Format 
column.  

About the Polycom devices: Others will have to help you there. I have no 
good guess why you might have the issue only on speakerphone, but not in 
handset mode. Could it maybe be some kind of electrical grounding issue 
(instead of something caused by transcoding)?

Philipp