A&D TM-2440 Instruction Manual page 10

How to Extend the Life of the Backup Battery
When first using after purchase or after storing for a month or more,
replace batteries and charge the backup battery. It is enough if the
backup battery is charged for 48 hours or more.
(The backup battery is always charged by AA batteries.)
Replace with two new AA batteries when the battery indicator displays
.
When
measurement and data communication cannot be performed. Replace
two new AA batteries.
Remove batteries to prevent the recorder from liquid leakage of battery
if the recorder is not used for a month or more.
6. The Countermeasures When the Device Has an Error
Stop the operation and remove AA batteries. If battery terminals
are shorted, battery may be hot.
In a failure, the cuff may get hot during measurement,
please handle it with care.
Put the notice label of "Malfunction" "Do not use" on the
recorder. Contact your dealer.
Stop the recorder immediately when the measurement time is
above 180 seconds and the air pressure becomes above 299
mmHg.
is displayed at the battery indicator, the blood pressure
viii