NEC MOBILEPRO 700 Quick Manual page 16

The unit only operates when the lock is in the locked position.
Back-Up Battery
A low battery message appears when back-up battery power is depleted. Be sure to replace the back-up battery
immediately as described next.
When you see the following message, the back-up battery must be replaced.
Backup Battery Very Low
Save your data, turn off unit power, remove the stylus, and close the LCD/Touch Panel.
If you receive messages indicating that both the main battery and the sub battery (back-up battery) are very low,
replace the back-up battery first.
If depleted main batteries are not replaced, the back-up battery drains more quickly than normal.
Disconnect any cables attached to the unit, such as the AC adapter cable.
Have a new back-up battery available.
Only replace the back-up battery with the CR2032.
Using another battery type can result in an explosion or fire.
Turn the unit over and locate the Battery Cover Lock on the bottom of the MobilePro. Slide the lock to the unlocked
position.
Replacing the bay cover
WARNING