When reporting in Domestic format, the call must be acknowledged by the user who answers the incoming call. If the user fails to acknowledge the call, the system will call the next number in the list until the maximum number of call attempts are reached.
To acknowledge the call, the user needs to press the [#] key just once on their phone when he hears a Pause between the Siren Tone, then he will hear a descending Tone and phone will automatically hang up.