Uniden BT359 User Manual page 5

Connect the adapter to the power connector on the top of the headset,
then plug it into any standard 10 V AC (regular indoor) power outlet.
Use ONLY the power adapter supplied with the headset! Using any other adapter
could damage your headset, create a fire hazard, or cause a risk of electric shock!
Checking the battery
When the battery is low, the headset sounds an alert tone every 0
seconds. To check the current status of the battery, press
at the same time. The headset announces the battery status
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as "Battery low, " "Battery normal, " or "Battery high. "
Pair the Headset to Your Phone
Pairing "introduces" two Bluetooth devices and gives them permission
to connect to each other. If you want to use the headset with more than
one phone, you need to pair it with each phone separately. Once you
pair a phone to the headset, the two devices can connect automatically
whenever they can detect each other.
and
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