Installing The Battery In The Handset; Battery Charge - Panasonic KX-TG2227S Operating Instructions Manual

Settings
Installing the Battery in the Handset
Insert the battery into the handset as shown (_), matching the correct
polarity. Press the battery down until it places into the compartment (@).
When finished, close the cover.
Battery Charge
Place the handset on the base unit and charge for about 15 hours before
initial use.
,,The IN USE/CHARGE/HOLD indicator lights and a beep sounds.
OR
IN USE/CHARGE/HOLD Indicator
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