Tri-Band: A cell phone usually with 900/1800/1900 MHz. This works with T-mobile, but does not roam off of Cingular, as it does not have 850 MHz
Quad-Band 850/900/1800/1900: If you plan on doing international traveling and using a SIM card overseas, or roaming on T-mobile, you want this phone. Countries other then the U.S. use 1800/900 so if your traveling, then you may want it.
2G, 2.5G and 3G: The G stands for generation. These terms are used to describe how advanced the technology that a company uses is. 2G (2nd generation) describes a phone that can make calls, and use GPRS, but not at the same time. 2.5 G describes a phone that can make calls (now called voice) and has EDGE, but these cannot be used at the same time. 3G (3rd generation) describes a phone that has voice, and UMTS or HSDPA (even faster versions of GPRS and EDGE, explained below) and voice CAN be used at the same time as Internet.
UMTS: A type of internet that goes over 1Mb/s, pretty much the speed of broadband (Mod, please add to this and the next one)
HSDPA: An even faster type of internet
* #BAL# or #225# - Displays current postpaid balance.
* #MSG# or #674# - Displays SMS/MMS used.
* #MIN# or #646# - Displays minutes used.
* #NUM# or #686# - Displays your current phone number.
* *NUM or *686 - plays back phone number of current SIM.
* #PWO# or #796# - Turns voicemail security on or off.
Sample: Voicemail password has been turned ON/OFF. To turn this feature ON/OFF, dial #PWO# again.
* #PWD# or #793# - Resets voicemail password.
Sample: Your voicemail password has been reset to the last 4 digits of your mobile number.
* #999# - Prepaid balance.
* *ADD or *233 - Add minutes to your prepaid T-Mobile To Go account with a credit card or electronic check.
