Common problems and solutions
Model ZT728 ZT778 KS28 U600

Problem: the device can not be powered on.
Solution:
1 recharge the battery 2 check if the battery is correctly installed, 3 check if the contact points of the battery are deformed.

Problem: the device can not be charged.
Solution:
1 check if the connection between adapter and mobile phone is correct, 2 check if the battery is useable, 3 if a battery is not charged for a long time, it can only be charged after a short period of time.

Problem: the network is not stable
Solution:
1 maybe the signal is weak, check if there is any interference around. 2 check if the SIM cark is correctly installed, 3 observe the signal indicator on the screen to see if the signal intensity can been shown normally.

Problem: can not make a phone call
Solution:
1 check if you are within the service range of the network, 2 the call function is restricted, 3 your telephone charges owed.

Problem: can not receive a phone call.
Solution:
1 check if you are registered to the network, 2 your telephone charges owed, 3 you have set call forwarding function. 4. the calling party is in your black list.

Problem: the handwriting can not respond quickly
Solution: 1 the contact screen can not respond quickly, so you need to re-calibrate it, 2 restore to default settings.

Problem: songs can not be played.
Solution:
1 if the song has been deleted or renamed, 2 if the song is under “my music” catalog, only songs with mp3 format can be played.

Problem : photo is not clear.
Solution: 1 do not twittering when taking picture, 2 the lens of the camera is covered with a protective film.

Problem: films can not be played
Solution: this device only supports standard MP4. The image resolution is 240X320.