Zte ZT303 User Manual page 125

(4 to 8 digits) help to protect your SIM card against
unauthorized use. If your SIM is locked, select "Activate",
Enter PIN code then activate SIM Lock. You should
enter the correct PIN code to access if Power On next
time.
PUK codes
The personal unblocking key (PUK) code and the
universal personal unblocking key (UPUK) code (8
digits) is required to change a blocked PIN code and
UPIN code, respectively.
The PUK2 code (8 digits) is required to change a
blocked PIN2 code. If the codes are not supplied with
the SIM card, contact your local service provider for the
codes.
If your SIM Lock is activated currently, select
"Deactivate" the close PIN code Security.
Note: If you enter wrong PIN code for three times,
SIM card will be locked, then you should Unlock it
by PUK code. If the codes are not supplied with
the SIM card, contact your local service provider
for the codes. The defaulted PIN code usually is
1234, please change it to your own setting code.
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