I have a site with an IP Office 500V2. They have 2 remote sites with 2 or so phones at each with no control unit. The sites are connected over a vpn tunnel.

When the remote sites get calls coming from external callers, the call quality sounds fine. If they call between the main site and remote site, they have poor call quality.

I set up network monitoring at the sites. They do not seem to have an issue with bandwidth. QoS is set up on the routers for the voice traffic over the VPN.

Does anyone have an idea what I could try?

The compression mode is set at automatic select on the extensions.

Are the main site phones also IP Phones? Did they try a alog or digital station?
Play with the "Allow direct mediapath", the codecs and other related VoIP settings.
Sounds like the IP Phones always use the VCM circuits.

If it ain't dutch it ain't much

Thanks.

I will give it a shot.

applying qos will have very little impact unless the conection is a point to point and you control both ends or a mpls with qos applied .what sort of conection is it and what is its bandwith.is it used for data as well??

Turning off "Allow direct media path" on the extensions fixed it.

Thanks for the help.

Then you have routing issues for sure!

BAZINGA!

I'm not insane, my mother had me tested!

@intrigrant and @jcallen03

Would this 'turning off' be beneficial too with SIP extns?

Could be, it is always the first thing I try when having voice issues with VoIP.

If it ain't dutch it ain't much