GSM - Global System for Mobile communications. A world standard for digital cellular communications using narrowband TDMA (Time Division Multiple Access), which allows up to eight calls at a time on 800 MHz and 1800 MHz frequencies. Introduced in 1991. Is the standard most commonly used in Europe and Asia, but not in the United States. GSM phones use a Subscriber Identity Module (SIM) smart card that contains user account information. Any GSM phone becomes immediately programmed after plugging in the SIM card, thus allowing GSM phones to be easily rented or borrowed. SIM cards can be programmed to display custom menus for personalized services.GSM provides a short messaging service (SMS) that enables text messages up to 160 characters in length to be sent to and from a GSM phone.

UMTS - Universal Mobile Telecommunications Service, also called WCDMA, is a 3G (Third Generation) packet-based transmission of text, digitized voice, video, and multimedia at data rates up to 2 Mbps. It is based on GSM standard and is supported by major standards bodies and manufacturers

Form Factor - Refers to the form factor of a phone. The main handset designs are bar, clamshell, slide, swivel

Dimensions - Phone's dimensions

Weight - Phone's weight

Technology - Refers to the type of the color displays. There are five major types: LCD, TFT, TFD, STN and OLED

Resolution - Refers to the width and the height of the display

Colors - Shows the number of colors that the display supports

OS - Operating system, which is the software that enables and controls the basic operation of an electronic device. The major OS for mobile phones are UIQ over Symbian, Microsoft Mobile for Pocket PC Phone Edition, Microsoft Mobile for Smartphones, Linux, Palm

Resolution - Shows the particular phone's camera resolution. The major mobile phone camera resolutions available are QCIF; CIF; VGA (640x480); 1, 1.2, 1.3, 2.0 and 3.0 megapixels.