Background noise cancellation takes place at the microphone.
This works by lowering the volume of loud ambient sounds. Only speech is not lowered before being transmitted to other group participants.
The ambient listening function takes place at the ear defenders. When the ambient listening function is active, noise cancellation is suspended and ambient background noise can be heard virtually as if without hearing protection (up to a volume of 82 dB). As such, the ambient listening function only affects the individual user, unlike background noise cancellation.