Siemens SL45 was the first mobile phone with memory expansion and an MP3 player, which debuted in 2001. An improved version, the SL45i, was also the first phone to have a Java virtual machine.
In addition to the MP3 player, SL45 offered other advanced features such as dictaphone with several hours of recording time, auto responder, voice dialing and voice commands, WAP browser, and context sensitive help in several languages. Other software include calendar/organizer, alarm clock, stopwatch, calculator, currency converter and games. While SL45 was one of the most advanced phones in its time, it was also one of the smallest.
Read more about Siemens SL45: Versions, Features and Specifications, Criticism, Firmware, User Base