XLR Pinout and Wiring: 3-Pin Connector Data

Figures on this page were checked October 2026. Every table row carries its source and access date.

XLR pinout: three contacts, three jobs

The XLR connector is the round, latching 3-pin plug that dominates professional audio wiring. IEC 60268-12, the standard on connector use in broadcast and similar sound systems, covers exactly this class of circular connector and prints the contact arrangement and contact designation for each application.

Gender follows the signal: male connectors with pins sit on output sides, female sockets on inputs, which is why mic and line inputs on mixers are female while cable ends and transmitter outputs are male. Musical Fidelity dates the modern agreement on these functions to the EIA RS-297-A standard, followed on its account since about 2000, and Neutrik lists IEC 61076-2-103 as the compliance standard for its NC3MX 3-pin cable connector.

Electrical specifications (Neutrik NC3MX datasheet)

These are contact-level numbers for one current connector family, not a property of every XLR on a panel. They do explain the connector's headroom: 16 A per contact is far beyond anything an audio signal asks for, which is why the same shell family survives in lighting and power variants.

Balanced wiring: why the third pin exists

A balanced line uses three separate conductors: two signal legs, one carrying the in-phase signal and the other its mirror image, plus the shield. The receive stage amplifies only the difference between the legs, so interference that hits both legs equally cancels. That is the job pin 3 does in this pinout, and it is why long cable runs in studios and on stage favor this connector over consumer plugs.

Rane's interconnection guide adds the grounding half of the design: standard XLR cables tie the shield to pin 1 at each end, and the receiving equipment should tie pin 1 to the metal chassis right where the cable enters, a method the note credits to the AES48 standard. Done this way, the note says, balanced interconnects deliver hum-free results; unbalanced runs get no such guarantee, which is why Rane tells readers to keep any unbalanced cable under ten feet (three meters).

Phantom power rides on the same pins

Mic inputs often feed a DC supply down the two signal legs to power condenser microphones. IEC 61938, the guide to analogue interface interoperability, added phantom supply variants to its second edition, including P48, the 48-volt variant. The supply is called phantom because, on a balanced input, it appears equally on pins 2 and 3 relative to pin 1 and carries no signal of its own.

The practical point for wireless sources is at the input, not the receiver: phantom is a mic-input feature, and the feeds live on the same three contacts you are about to plug into. If a mixer or interface offers phantom on an input, check that device's manual before connecting any line-level source, and leave the +48 V switch off when the source is not a condenser microphone that needs it.

From XLR to consumer plugs

Adapters between this world and home stereo gear exist, but the two sides differ in more than the plug: Shure's level primer puts consumer line equipment at -10 dBV nominal and professional equipment at +4 dBu, with mic level about a thousand times weaker than line. Our RCA connector reference covers the consumer side and its level discipline, and the optical audio reference covers the digital exit. For a working example of this connector in service, the Yamaha EMX512SC powered mixer archive shows the input block you would be feeding.

Going wireless on XLR

The wireless path is short: a Bluetooth receiver with a balanced XLR output replaces the cable from the rack. It needs to respect the electrical context above, line level into line inputs, phantom off, and then the connector does what it has done since the RS-297-A era, carry a clean three-conductor feed across the last few meters. The receiver below is that piece for racks, powered speakers and mixer inputs.

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