Huawei ETS2028 User Manual page 19

If the FWT is connected to the power adapter and the
spare battery is inserted, the FWT is powered by the
power adapter, and meanwhile, the spare battery is
charged.
Charge the spare battery for at least eight hours for the
first time. If a fully-charged spare battery is left unused
for a long time, charge it for at least five minutes before
using it again.
If the FWT is powered solely by the spare battery, the
talk time is three hours to five hours or the standby time
is 40 hours to 120 hours (the talk time and the standby
time are network dependent).
Installing the Power Adapter
Press and hold to power off your FWT. Connect the power
adapter to the FWT, and plug it to the power socket.
Installing the Spare Battery
Press and hold to power off your FWT and then disconnect
the FWT from the power socket. Then install the spare battery
as shown in the following figure. When installing the spare
battery, make sure that the battery cord plug matches the
battery jack. Do not insert reversely.
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