Call quality degrades when connected to TPV

[viciuser]

Some days I have issue with call quality when line is transferred to TPV. When my agents are taking calls and talking with customer call quality is clear and great. However, once any one of them transfer the customer to TPV in Florida, US. Then the call quality between TPV and customer breaks, echos and becomes unaudible to talk and further. We are dialing outbound to US. This is not happening daily but on some days only. What could be the reason for this issue? My minutes provider say they have enough lines allocated and is not minutes issue. If it is minutes issue it should have affected the calls between agents and customers as well. Could it be something to do we dialer configs?

[gardo]

Astguiclient and Asterisk version?