Only one base station in the mirrored pair acts as the master base station at any time. The initial selection is done through the base station menus of the selected member of the mirrored pair.
Before you begin
This process requires access to tabs and fields currently only visible when Show Advanced Options is selected.
Procedure
Login to one of the mirrored master base stations.
Select DECT and then select the Master tab.
Click Activate mirror. That base station is made the currently active master base station in the mirrored pair.