What is XLR connector?

Fermale and male XLR connector

The XLR connector is a style of electrical connector, primarily found on professional audio, video, and stage lighting equipment. The connectors are circular in design and have between 3 and 7 pins. They are most commonly associated with balanced audio interconnection, including AES3 digital audio, but are also used for lighting control, low-voltage power supplies, and other applications. XLR connectors are available from a number of manufacturers and are covered by an international standard for dimensions, IEC 61076-2-103. They are superficially similar to the older and smaller DIN connector range, but are not physically compatible with them.

1 Chassis ground (cable shield)
2 Positive polarity terminal for balanced audio circuits (aka "hot")
3 Negative polarity terminal for balanced circuits (aka "cold")

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