Panasonic NS1000 Manual page 269

3.7 System Alarms via PT
Settings to notify the system alarms via IP-PT
The extension numbers of IP-PTs that can display System Alarm Information.
Setup -> PBX Configuration -> 11.1 Main -> Maintenance Tab
Specify the extension numbers.
The System Alarm button setting (PT Flexible Button)
Setup -> PBX Configuration -> 4.1.4 Flexible Button
Select "System Alarm" as Type.