What are the AC power failure settings on the Vea panel?

The Vea 3G/4G GSM system has a few different options available for what happens when the AC power is disconnected from the main panel.

Vea 3G/4G GSM Power Failure Settings:

0 =
No alerts / nothing happens

1 =
The screen of the panel will display an alert.

2 = 
The screen of the panel will display an alert.
The system will call out to any programmed phone number(s).

3 = 
The screen of the panel will display an alert.
The system will call out to any programmed phone number(s).
(Same as 2)

4 =
The screen of the panel will display an alert.
The system will call out to any programmed phone number(s).
The sirens will sound.

5 = 
The screen of the panel will display an alert.
The system will call out to any programmed phone number(s).
The sirens will sound.
(Same as 4)