Mobile phone is a telephone that can make and receive calls over a radio-frequency carrier while the user is moving within the service area. The radio frequency link establishes a connection to the switching systems of a mobile phone operator, which provides access to the public switched telephone network. Modern mobile telephone service uses a cellular network architecture. In addition to telephony, modern mobile phones also support a variety of other services such as text messaging, MMS, email, Internet access, short-range wireless communications, business applications, gaming, and photography. Mobile phones that offer these and more general computing capabilities are referred to as smartphones.