A smart phone is a mobile phone that offers advanced functionality beyond making calls and sending texts, such as LCD screens for emailing and web browsing. Some key features of smart phones include advanced call management, digital answering machines, and connectivity options like USB, infrared, Ethernet, and wireless. Popular smart phone manufacturers include Apple, HTC, Samsung, Nokia, and Micromax. Common operating systems are Android, Windows Mobile, iOS, BlackBerry OS, and Symbian. Some of the earliest smart phones were the IBM Simon in 1993, Motorola Envoy, Nokia 9000 Communicator, and Fujitsu Stylistic tablet PC.