4 pin XLR male connector.
4 pin XLR female connector.
The 4-pin XLR is a circular multipole connector conforming to the 19 mm shell format defined by IEC 61076-2-103:2004, sharing its locking latch mechanism with the broader XLR family. Its most widespread professional application is the mono intercom headset: Pin 1 carries the microphone screen/earth, Pin 2 the microphone signal, Pin 3 the headphone return, and Pin 4 the headphone output — a pinout common to Clear-Com, Canford, and other partyline intercom systems. Beyond communications, the 4-pin XLR was adopted by a range of theatrical lighting devices including scrollers, strobes, and gobo rotators, where manufacturers assigned their own proprietary signal allocations.
| Pin | ||
|---|---|---|
| Application | 1 | 2 |
| AMX 192 | screen (analogue 0V) | clock + |
| Canford Talkback 1cct headset | Mic earth/scr | Mic signal |
| Clearcom talkback headset | Mic earth/scr | Mic signal |
| Diversitronics (analogue) superstrobes | signal | ground |
| Pancan (Memory System) data | ||
| Pyro Pack Control | channel 1 | channel 2 |
| Rosco gobo rotator | Forward A | Reverse A |
| Scroller (generic) | ground | -ve data |
| Wybron Scroller | +24v DC | -ve data |
Notes
- The 4-pin XLR shell is mechanically defined by IEC 61076-2-103:2004, which covers circular multipole XLR connectors with a nominal 19 mm outer shell diameter and 3 to 7 contacts.
- Pin assignments are not standardised across applications: each manufacturer or protocol defines its own allocation, so cables are generally not interchangeable between different 4-pin XLR devices.
- For intercom use (Clear-Com, Canford), the full 4-pin headset pinout is: Pin 1 = Microphone Screen, Pin 2 = Microphone Input, Pin 3 = Headphone Return, Pin 4 = Headphone Output.
- Lighting-control devices (scrollers, strobes, gobo rotators) each implement proprietary signal schemes; always verify the manufacturer’s wiring documentation before connecting equipment.
- The Wybron Scroller carries +24 V DC on Pin 1, making polarity and voltage verification essential before connection.
Signals
- Mic earth/scr (Pin 1, intercom) — Microphone screen/earth connection; provides shielding and establishes the signal reference for the microphone circuit.
- Mic signal (Pin 2, intercom) — Microphone audio input from the headset.
- Headphone return (Pin 3, intercom) — Return (common) conductor for the headphone circuit.
- Headphone output (Pin 4, intercom) — Audio signal to the headphone earpiece.
- screen / analogue 0V (Pin 1, AMX 192) — Shield and analogue ground reference for AMX 192 lighting control data.
- clock + (Pin 2, AMX 192) — Positive clock signal in the AMX 192 protocol.
References
- XLR FAQ — Neutrik
- Headset Connectors — Clear-Com V-Series Iris Online Manual
- IEC 61076-2-103:2004 — Connectors for electronic equipment — Circular connectors — Detail specification for multipole connectors (type ‘XLR’). International Electrotechnical Commission, 2004.