21-pin socket used to interconnect satellite receivers, television sets, and other audiovisual equipment.

Speaker systems – 2.1, 5.1, 7.1

2.1 – These systems do not use the rear and centre speakers, leaving only the sub-woofer and two front speakers. 5.1 – Three front speakers, positioned to the left, right and centre at the front of the room, but also includes two rear speakers positioned...