China mobiles secret codes

CHINESE MODELS:

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
Service codes **x, 5xx:
software version: *#79#
software version: *#837#
Service codes VK200, VK2000, VK2010, VK2020, VK4000:
software version: *#79#
service menu: *#9998*8336# (hold #)
reset defaults (phone/user code reset to default): *#9998*7328# (hold #)