Samsung SPH-M400MSASPR - Manual (Page 8)

Get Started 2
 Replace the battery compartment cover, making sure all the tabs are secure and
there are no gaps around the cover.
2. Insert the USB cable into the phone’s Charger/Accessory jack.
3. Plug the charging head into a standard AC power outlet.
Always use a Sprint-approved or Samsung-approved desktop charger, travel charger, or vehicle
power adapter to charge your battery.