Service menu and secret codes
What is Service menu?
 Service menu is extra menu in phone with some network (BTS adress, channel, signal quality, ...) and
 phone (task, battery, ...) information.

And what is secret codes?
 There are three secret codes. One for turn Service menu ON, one for more detailed version info and one for
 exitcode information (what task and why reset or power off the phone).

How to enable this codes?
1. You need to have this entry in phonebook:
    Type: PHONE or SIM
    Name: DEBUG (for J70 use name: TALES)
    1st number: Your SIM card IMSI (15 digits, no spaces)

2. Go to Menu/Settings/Preferences/Factory Reset dialog with "Yes" and "No" buttons and enter:

*#prege#*#77343#Enable Service menu (for J5/6)
*#sonymon#*#7669666# Enable Service menu (for J7x)
*#release#*#7353273#Show extended release info
*#exitcode#*#39482633#Show exitcode info (work without phonebook entry DEBUG too)

3. If You enabled service menu, You must reenter menu system. Go to the main screen with wallpaper and operator
 name and enter menu again. Between Messaging and WAP will be new menu.

How to get SIM card IMSI?
1. Using data cable with AT terminal (HyperTerminal in Windows)
 Send AT+CIMI command and you will get IMSI.

2. Using CTE terminal
 Send READIMSI command and You get 15-digit IMSI. You need enabled all CTE commands.

 Download Monitor Mode documentation 

James Bond feature
 There are one another service feature: display last not-normal exitcode.

1. You need to create phonebook entry like DEBUG (with IMSI), but name it JamesBond.
2. Now You can view last exitcode on main screen with wallpaper (see screenshot).
3. If You don't see anything, try this: Restart the phone to the PIN-Entry screen and wait, until
    it automatically power-off. Now You can see something like on my screenshot.

Some screenshots

resetdlg.gif
Here enter the codes
release.gif
Advanced version info
exitcode1.gif
Exit info screen
monitormode.gif
Monitor menu position

monitormode_run.gif
Monitor mode menu
servingcell.gif
BTS info
ncells.gif
All heard BTSs
stats.gif
Statistics

power.gif
Power info
memusg.gif
Memory Usage
causecodes.gif
Cause codes
causecodes.gif
James Bond feature