More phones are korean versions. you should change the network for internalal setting.
chk the phne model no.
rmbr the ending chactor. it's mean who is the ntwrk provider in kr.
319712358 dial hidden ntwrk sttng
ok
pw for
S 996412 SK
L 0821 LG U+
K 774632 KT
network setting
netwrok mode FOR SL
WCDMA 2100 BEST OR WCDMA 1900
FINISH
FOR KR
LTE 1800 OR 850
