[Asterisk-Users] Polycom 501 horrible echo

[Adam Goryachev]

On Mon, 2006-01-23 at 20:46 -0500, Jeff Herring wrote:
> Issue: horrible echo (and squeals, and "underwater-like" sound) on speaker
> phone when calling from extension to extension.

Is it a direct call from one extension to another, or a meetme, or
something similar?

> echo not present when calling outbound using PRI or when receiving calls 
> from PRI.

echo cancel is done by zaptel I presume..

> echo not present when using handset or headset in any case.

No echo due to feedback between phones probably.... (polycom doesn't
include any EC for handset/headset I think)

> I suspect the issue is related to the echo cancelation HW in the speaker 
> phone, but I'm not sure...The unfortunate thing is these phones were 
> purchased because of their excellent speaker phones which now appear to
> be worse than the Grandstreams!

Well, I have the same problem if I call to my mobile, and have both
phones on speaker... or two phones on the same desk with one phone on
speaker and the other on handset even produces the same result.
IMHO, that is normal and to be expected.... I can't remember the
technical name right now, but if you can create a 'loop' in the audio
between the speaker of one phone and the mic of the other, then you will
get this result....

> Anyone with thoughts of where to start?

Move the phones further apart, turn down the volume of the phones, don't
use speaker :)

Good luck, perhaps I'm wrong, and the above should work.... 

Regards,
Adam