IBM Simon, the first touchscreen phone, went on sale in 1994

IBM's Simon Personal Communicator, introduced in 1992, became the first touchscreen mobile phone sold commercially when it went on sale on August 16, 1994. The device combined cellular communications with personal digital assistant functions and a resistive touchscreen. Simon featured a 4.5-inch display that responded to pressure or a stylus rather than finger touch. It shipped with applications including email, fax, calendar, contacts, note-taking, calculator and drawing tools, and ran a custom operating system derived from GEOS on a 16-megahertz processor with 1 megabyte of RAM. Only about 50,000 units were sold, and production ended in 1995 because of the phone's large size and limited battery life. Later touchscreen models such as the Alcatel One Touch Com in 1998, the Ericsson R380 in 2000 and the Nokia 7710 in 2004 reached the market but none achieved widespread adoption.