China Mobile 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
Default user code : 1122, 3344, 1234, 5678

secert codes which i work on are
1) *#06#--emi 
2) *#87*#--for version code and all
3)*#66#---for test

*#4960# send ----> info
*#3210# send ----> sp lock
*#2820# send ----> version
*73738# send ----> hardware reset
Other codes :

*#2220# send ----> reset to default
*#2634# send ----> unlock gprs settings
*#1110# send ----> special net unlock
*#8140# send ----> net lock
#4960*code# send ----> unlock
#4960*code*code # send ----> unlock