Mitel SX-200 Documentation page 257

S C
E TION
NON-VOLATILE RAM BATTERY ALARM
Page 202
Description
On a power-up reset, there is a test performed to check the status of
the NVR battery back-up. If the battery switch is OFF, a MAJOR alarm
proximately every 5 minutes. If a problem exists a MINOR alarm
will display "1" if the battery switch on the module is OFF. The first
three digits of the destination display will display "2" if the battery
voltage is out-of-tolerance.
Conditions
The batteries can refresh the RAM for an entire week if the card is not
connected to a system.
Programming
None
Operation
None