 
 <prompt> MP3 players dey mainly play wetin kind entertainment? Given di previous question, write one context wey contain di answer. E fit be 1 - 20 sentences. Context: <response>: Na only for di 1980s digital telephony transmission networks start dey possible, like ISDN networks wey dey assure minimum bit rate (usually 128 kilobits/s) for compressed video and audio transmission. During dis time, dem dey research other forms of digital video and audio communication. Many of these technologies, like the Media space, no dey widely used like videoconferencing but dem still dey important for research. The first systems wey dey dedicated start to show for market as ISDN networks dey expand worldwide. One of the first commercial videoconferencing systems wey companies buy come from PictureTel Corp., wey do Initial Public Offering for November, 1984. 