Audio cables some in a wide range of shapes and sizes. 3.5mm jacks are arguably the most common - they can frequently be found on mobile devices and laptops as a way to connect headphones. RCA Phono cables are commonly used when connecting equipment in the home and DJ audio systems, PC audio, and in speaker systems for TVs and games consoles. XLR, 1/4" jacks and Speakon cables tend to be used for musical performance, often associated with microphones and musical instruments.