Adjust FXO (Analog Line) Ports Volume:
This describes adjusting the rxgain and txgain for the Analog line ports. This is sometimes required for echo cancellation, where the line volumes are too loud for software echo cancellation to work effectively. For echo cancellation try set both rxgain and txgain to -5, then test call quality and adjust again as needed until the echo is gone.

1. Open your web browser and enter the IP address or hostname of your server in the address bar (ex. http://192.168.1.115) then press enter.
2. You should Freevoice PBX User page should now be displayed.
3. Switch into Admin Mode by clicking the switch link next to User mode in the top right corner.
4. Enter maint for the user, the default password is freevoice.
5. Move the mouse over the Asterisk tab, and click on Config Edit.
6. At the Config Edit page scroll down and click on zapata.conf
7. Find the rxgain and txgain options and adjust as needed, this can be a positive or negative number.
8. Click the Update button in the bottom left corner when done.
9. Click the Re-Read Configs tab to reload Asterisk

The Config Edit page will allow you to edit configuration files for Asterisk and any VoIP phones. This is for advanced users, inappropriate changes to the configuration files can cause serious harm! Editing of these files is only required in very few situations, such as FXO/FXS card settings, echo cancellation, and custom dialplan scripting.