full list of the codes and how to use them. By typing in the following secret USSD codes on the dialpad of the phone then pressing the call button you can bring up these tricks:
*3001#12345#*:Field Test mode
*#5005*7672#: SMS centre number*3370#: Turn on or off EFR (Enhanced Full Rate), a mode that improves your iPhone’s call quality
*#06#: Find out your iPhone’s IMEI number
*#31#: Hide your number on calls option
*#43#: Check if call waiting is on or off
*43#: Turn on call waiting
#43#: Turn off call waiting
*646#: Check minutes left on contract
*225#: Find out your current mobile account balance
*777#: Find out prepaid account balance
*#61#: Number of missed calls
*#21#: Call forwarding status
*#67#: Call forwarding number
*#33#: Find out what mobile services are disabled on your phone
*3001#12345#*:Field Test mode
*#5005*7672#: SMS centre number*3370#: Turn on or off EFR (Enhanced Full Rate), a mode that improves your iPhone’s call quality
*#06#: Find out your iPhone’s IMEI number
*#31#: Hide your number on calls option
*#43#: Check if call waiting is on or off
*43#: Turn on call waiting
#43#: Turn off call waiting
*646#: Check minutes left on contract
*225#: Find out your current mobile account balance
*777#: Find out prepaid account balance
*#61#: Number of missed calls
*#21#: Call forwarding status
*#67#: Call forwarding number
*#33#: Find out what mobile services are disabled on your phone