Echo canceller

Hi all!

I have a freepbx 2.9 machine running with 2 openvox B200P ISDN card. It’s configured with default DAHDI installed.

When someone call outside, the called person is hering his voice with e little latency, so he is hearin echo.

I want to know how to install 4 licenses of echo canceller, and what id your experience with this issue.

4 channels are activated for comunicating with otside, so 4 calls can de done.

Any help please??

Regards

Can anyone help me please?? I will be very pleased to you.
Thanks