China Mobile Phone Secret Codes

default user code: 1122, 3344, 1234, 5678
Engineer mode: *#110*01#
Factory mode: *#987#
Enable COM port: *#110*01# -> Device -> Set UART -> PS Config -> UART1/115200
Restore factory settings: *#987*99#
LCD contrast: *#369#
software version: *#800#
software version: *#900#
set default language: *#0000# Send
set English language: *#0044# Send
set English language (new firmware): *#001# Send

I donot know about the following codes but try them, they may be engeneering codes

*#0086#, *#0886# set to China
*#0084#, *#0966# set to Vietnamese
*#77218114#
*#19992006#
*#881188#
#*94267357#
*#0084#call