This parameter is used when the level control mode is set to AUTOMATIC.
Set to 0 to amplified the signal to its maximum value and -40 attenuate the signal to a minimum value. The recommended value is -18 dBM0.
The ALC algorithm is designed to adjust the level of the talker to a user-defined target energy level. The gain applied can be negative or positive, resulting in either amplification or attenuation of the signal, depending on the target level. While the gain is applied on the whole signal (i.e. voice and background noise), only the energy of the talker is used when deciding to amplify or reduce the signal. For this purpose, a voice activity detector specific to the ALC algorithm (ALC VAD) is used to differentiate between voice and noise signals.