Panasonic KX-NS1000 Feature Manual page 39

SIP CO lines can be configured to switch their operation to the Backup Master unit.
ITSP
SIP CO line
PBX
Master Unit
Isolated Mode
If no PBX is designated as the Backup Master unit, or if the Backup Master unit also goes offline, Slave units
will operate in Isolated mode if they are set to do so.
In Isolated mode, each PBX will provide service to the extensions registered to it and for the CO lines connected
to it.
Master Unit
PBX
Offline
PBX
Isolated
mode
Conditions
IMPORTANT
In Backup Master mode and Isolated mode, there are no restrictions on performing software upgrades
(® 20.1.97 Upgrading the Software). However, if an upgrade is applied while any unit is offline, the offline
unit will no longer be able to participate in the One-look network because its software version will be different
from the other PBXs' software version.
The One-look network will switch to Backup Master mode or Isolated mode if there is no response from
the Master unit (or Master Backup unit) within a preset Master Site connection monitor time.
Document Version 2016-03
PBX
Slave Unit 1 Master Unit
(Backup Master Unit)
Slave Unit
(Backup Master Unit)
PBX
Offline
PBX
: Current Connection
: Lost Connection
3.1.1 Backup Master Mode and Isolated Mode
ITSP
SIP CO line
Offline
PBX
PBX
Slave Unit 1
(Backup Master Unit)
Isolated
mode
Feature Manual 39