There are three categories of mobile phones.
# Basic phones can make voice calls, send and receive SMS (short message service) messages and make use of USSD (unstructured supplementary services data).
# Feature phones offer features additional to a basic phone, including cameras and increased storage, as well as the ability to access the Internet. Feature phones usually have a standard numeric keypad.
# Smartphones offer advanced capabilities and features over feature phones, notably allowing users to add applications to their phones. These phones run a full-featured operating system; most have 3G (third-generation) as well as Wi-Fi (wireless-fidelity) capabilities and generally have a QWERTY keypad.
