*3001#12345#*- Opens up the “Field Test” settings on your iPhone, which allows you to see many, many advanced network settings on your phone including cell site information and more.
*#06# – Displays your iPhone’s International Mobile Equipment Identity (IMEI) number (this code also works on many other phones).
*#21# – Displays any call forwarding settings enabled on your iPhone.
*#43# – Shows you if call waiting for various parts of your phone are either enabled or disabled.
*#30# – Shows you if you have the call presentation (to see who is calling you) setting enabled or disabled.
*#33# – Displays call barring settings for your iPhone, and weather they are enabled or disabled
iPhone Codes: Carrier & Billing Information
*646# -View available minutes on your AT&T plan (*min#).
*#06# – Displays your iPhone’s International Mobile Equipment Identity (IMEI) number (this code also works on many other phones).
*#21# – Displays any call forwarding settings enabled on your iPhone.
*#43# – Shows you if call waiting for various parts of your phone are either enabled or disabled.
*#30# – Shows you if you have the call presentation (to see who is calling you) setting enabled or disabled.
*#33# – Displays call barring settings for your iPhone, and weather they are enabled or disabled
iPhone Codes: Carrier & Billing Information
*646# -View available minutes on your AT&T plan (*min#).