This parameter specifies the gain in decibel to applied on the signal transmitted to an analog interface.

A positive value increases the volume of the signal.

A negative value decreases the volume of the signal.

Set this parameter to 0.0 to keep the signal untouched

Valid values for a FXS interface are: -3.5, 0.0 and 3.5 dB.

Valid values for a FXO interface are: -15.0 to 12.0 dB.