The common components found on all phones are:
A battery, providing the power source for the phone functions.
An input mechanism to allow the user to interact with the phone. These are a keypad for feature phones and touch screens for most smartphones.
A screen which echoes the user's typing displays text messages, contacts, and more.
Basic mobile phone services to allow users to make calls and send text messages.
All GSM phones use a SIM card to allow an account to be swapped among devices. Some CDMA devices also have a similar card called an R-UIM.
Individual GSM, WCDMA, iDEN and some satellite phone devices are uniquely identified by an International Mobile Equipment Identity (IMEI) number.
Low-end mobile phones are often referred to as feature phones and offer basic telephony. Handsets with more advanced computing ability through the use of native software applications are known as smartphones.