3.5mm Audio is an analog audio connection using a "TRS connector." TRS, or Tip/Ring/Sleeve, is named for its segmented design. 3.5mm is the standard audio connection for most personal music players and analog computer audio. Smaller versions of the standard, like the 2.5mm plug, are often used on cell phones; while larger versions, like the 1/4" plug, are used in audio/musical equipment such as microphones, guitars, and loudspeakers.