[Asterisk-Users] Silence suppression /RTP VAD and Asterisk? Dropped calls on IP-500

[david.j as]

Hello,

I run Asterisk in a 100% VOIP installation with the Polycom IP-500 phones.
Every once and a while I have problems with either dropped calls
between Asterisk and my provider,  or invalid RTP audio streams with
phones behind NAT.  I have had a few Asterisk developers look into my
installation and even my provider check my setup but still am having
problems.  They tell me that I need to disable silence suppression on
the IP-500 because Asterisk won't support it and either Asterisk or
the MG thinks the call is dropped in abstence of RTP packets.

 However I can't find any reference to this in the Polycom manual. 
Does anyone know how to turn VAD/Silence suppression on the Polycom --
or if it even supports it?  Is there a work around with Asterisk? 
Thanks in advance.

David