Just some important codes for your mobile device, that might be sometimes handy (use follows at your own risk):

Type *#61# and press call – Check redirection status.
Cancel all redirections: ##002#
*43# to activate call waiting, to deactivate #43#.
If your phone doesn’t have incoming call barring and outgoing call barring, you can try this.
For outgoing call barring dial *33*barcode*# and pres OK. To deactivate it dial #33#barcode*#.

On any phone on any network type in **43# to enable conference calls. You can make up to 7 calls at once

If you need to block SMS reception (if you are spammed by someone) just press this code:
*35*xxxx*16#
xxxx is your Call Barring code (default is 0000).
To remove this barring type: #35*xxxx#

If you want to hide/show your phone number when calling, put one of these codes below in front of the number that you are going to call.
(*#30# / *#31# or *31# / #31# ) Works on some networks.

Typing *0# or *nm# on the beginning of a txt message gives you detailed delivery report on some networks. But turn off reports in message settings before.
When the sim card-pin blocked type
**042*pin2 old*newpin2*newpin2*

Further codes:

Software version: *#9999#
IMEI number: *#06#
Serial number: *#0001#
Battery status- Memory capacity : *#9998*246#
Debug screen: *#9998*324# – *#8999*324#
LCD kontrast: *#9998*523#
Vibration test: *#9998*842# – *#8999*842#
Alarm beeper – Ringtone test : *#9998*289# – *#8999*289#
Smiley: *#9125#
Software version: *#0837#
Display contrast: *#0523# – *#8999*523#
Battery info: *#0228# or *#8999*228#
Display storage capacity: *#8999*636#
Display SIM card information: *#8999*778#
Show date and alarm clock: *#8999*782#
The display during warning: *#8999*786#
Samsung hardware version: *#8999*837#
Show network information: *#8999*638#
Display received channel number and received intensity: *#8999*9266#
*#1111# S/W Version
*#1234# Firmware Version
*#2222# H/W Version
*#8999*8376263# All Versions Together
*#8999*8378# Test Menu
*#4777*8665# GPSR Tool
*#8999*523# LCD Brightness
*#8999*377# Error LOG Menu
*#8999*327# EEP Menu
*#8999*667# Debug Mode
*#92782# PhoneModel (Wap)
#*5737425# JAVA Mode
*#2255# Call List
*#232337# Bluetooth MAC Adress
*#5282837# Java Version

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