Portable audio player
The purpose is to play music from audio cassettes. The device was powered by batteries. The first player was released by Sony in 1979.
Portable CD player
Cassette players were replaced by portable CD players due to the mass release of CDs. The first device was released by Sony in 1984.
MP3 player
In 1998, the little-known company SaeHan invented the MP3 format. Digital technologies have replaced CDs. These players are compact and convenient.