RCA Cables

• An RCA cable is a cable that has RCA connectors on the ends. These are the kind of connectors you use to hook up the components of a home theater system, with different color-coded jacks for the left and right audio signals -- usually white and red, respectively. An RCA cable may also have an additional wire for video data, with a yellow jack. Televisions, receivers, stereos and other such electronics are usually connected with RCA cables.
  
  

TRS Cables

• A TRS cable is an audio cable that uses a TRS connector, a little round striped jack. Headphone jacks, microphone jacks and other audio inputs you might find on a computer or electronic device use a small TRS connector. A larger size TRS connector is used for instrument cables (a.k.a. patch cords), the audio cables that musicians use to plug their instruments into amplifiers. TRS cables are also used for loudspeaker connections and effects pedal chains.
  
  

XLR Cables

• One thing that musicians don't use a TRS cable for is microphones. Instead, microphones are almost always hooked up with XLR cables. The XLR connector has an asymmetrical arrangement of pins and a little latch on one side so it can lock into place. Mixing boards used by audio engineers make heavy use of XLR cables for most of their connections. Some instruments or amplifiers also offer an XLR output, allowing them to be easily wired up to a mixing board.
  
  

Other Audio Cables

• Besides these basic types, there are others that are older or more specialized. The simplest is speaker wire, merely a cable of two wires that are exposed at either end. Some speakers have inputs made of little metal clamps that pinch the ends of speaker wire. Another audio cable is a MIDI cable, used to carry digital information for MIDI instruments such as keyboards. MIDI connectors have five pins arranged in a half-circle. Many loudspeakers now use Speakon cables instead of TRS cables, a modern type designed to handle higher current.