A mobile phone feature is a capability, service, or application that a mobile phone offers to its users. Mobile phones are often referred to as feature phones, and offer basic telephony.[clarification needed] Handsets with more advanced computing ability through the use of native code try to differentiate their own products by implementing additional functions to make them more attractive to consumers. This has led to great innovation in mobile phone development over the past 20 years.
A battery (typically a lithium-ion battery), providing the power source for the phone functions.
An input mechanism to allow the user to interact with the phone. The most common input mechanism is a keypad, but touch screens are also found in smartphones.
All mobile phones are designed to work on cellular networks and contain a standard set of services that allow phones of different types and in different countries to communicate with each other. However, they can also support other features added by various manufacturers over the years:
roaming which permits the same phone to be used in multiple countries, providing that the operators of both countries have a roaming agreement.
send and receive data and faxes (if a computer is attached), access WAP services, and provide full Internet access using technologies such as GPRS.
Push to Talk over Cellular, available on some mobile phones, is a feature that allows the user to be heard only while the talk button is held, similar to a walkie-talkie.