Maxcom MM721 User Manual page 11

Be careful while using your memory cards, especially while
installing and uninstalling them. Some memory cards must
be formatted on a PC before the first use. Make backup
copies of data stored on the cards used in other devices, if
you use SD cards! Misuse or other factors might cause
damage or loss of data stored on the cards.
Insert the battery so that the contacts +/- will face into
the phone. After inserting the battery, the battery
cover should be placed back and slightly pushed to
click into place.
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