Jack Pinout: 3.5mm TRS and TRRS Audio Connector Guide

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A jack pinout diagram shows the electrical contact assignments for 3.5mm (1/8") audio connectors, covering TRS (Tip-Ring-Sleeve) for stereo headphones and TRRS (Tip-Ring-Ring-Sleeve) for headsets with a microphone — including the two conflicting CTIA and OMTP wiring standards.

The 3.5mm (nominally 3.5 mm diameter barrel) audio jack is the most widely used small audio connector in consumer electronics. It is formally standardised under IEC 61076-3-104 and is colloquially called a headphone jack, aux jack, or mini jack. Understanding the pinout is essential for DIY cable making, adapters, repair, and troubleshooting.

TRS (three-conductor): three contacts — Tip, Ring, Sleeve. For stereo audio, the assignment is universally: Tip = Left channel audio, Ring = Right channel audio, Sleeve = Ground (common return for both channels). For balanced mono audio (professional applications), the assignment is: Tip = Hot (+), Ring = Cold (−), Sleeve = Ground/shield. TRS connectors are also used for insert send/return loops on mixing desks in a Y-cable configuration.

TRRS (four-conductor): four contacts — Tip, Ring 1, Ring 2, Sleeve. TRRS is used on smartphone and tablet headsets to add a microphone and in-line control functionality to a stereo headphone connector. Unfortunately, two incompatible wiring standards exist:

CTIA/AHJ standard (used by most modern devices — Apple, most Android, and current smartphones): Tip = Left audio, Ring 1 = Right audio, Ring 2 = Ground, Sleeve = Microphone.

OMTP standard (used by older Nokia, early Sony-Ericsson, and some older Android devices): Tip = Left audio, Ring 1 = Right audio, Ring 2 = Microphone, Sleeve = Ground.

The only difference between CTIA and OMTP is the position of Ground and Microphone (Ring 2 vs Sleeve). A CTIA headset on an OMTP device (or vice versa) will produce no microphone input and a degraded audio experience.

Connector sizes: the standard 3.5mm is by far the most common. The 6.35mm (1/4") TRS jack is used in professional audio and musical instruments. The 2.5mm TRRS was used on older mobile phones. TS (Tip-Sleeve, two-conductor) connectors carry mono unbalanced audio and are used on electric guitar and instrument cables.

How to wire jack pinout

Identify the connector type (TRS or TRRS) Count the insulating rings on the plug barrel. Two rings = TRS (stereo audio or balanced mono). Three rings = TRRS (stereo + mic). The number of rings equals the number of conductor boundaries, not the number of conductors.
Determine the applicable standard for TRRS (CTIA or OMTP) If the device is an iPhone, current Android flagship, or a device released after approximately 2012, CTIA (Ring 2 = Ground, Sleeve = Mic) is almost certainly applicable. For older Nokia, early Android, or unknown devices, test with both a CTIA and OMTP headset or use a multimeter to measure continuity between the sleeve and device chassis ground.
Strip and prepare the cable for soldering Strip approximately 30 mm of the cable outer jacket. Separate the conductors — typically coloured wire for Left (red or white), Right (green or blue), and bare or tinned copper for Ground. For TRRS cables, a fourth conductor (often red or pink) carries microphone. Twist and tin the bare ends with solder.
Thread the shell and strain relief onto the cable before soldering This is the step most beginners forget. Slide the jack housing (barrel and spring strain relief) onto the cable in the correct order before you solder. You cannot thread them on afterwards without desoldering.
Solder conductors to the correct contacts For TRS stereo: Left (red) to Tip lug, Right (green) to Ring lug, Ground (bare) to Sleeve lug. Use minimal solder — excess bridges the contacts. Work quickly to avoid heat damage to the plastic insulator between contacts.
Test continuity and isolation with a multimeter With all conductors soldered, use a multimeter in continuity mode to verify: Tip to the correct conductor at the far end (Left); Ring to Right; Sleeve to Ground. Then verify no continuity (short) between any two contacts.
Assemble the housing and strain relief Slide the shell body over the connector and tighten. Ensure the strain relief is positioned to clamp the cable jacket (not the inner conductors). Give the cable a gentle pull to confirm the relief is gripping.

Specifications

Connector barrel diameter	3.5 mm (also called 1/8" or mini jack)
TRS contact assignment (stereo audio)	Tip = Left, Ring = Right, Sleeve = Ground
TRRS CTIA assignment	Tip = Left, Ring1 = Right, Ring2 = Ground, Sleeve = Microphone
TRRS OMTP assignment	Tip = Left, Ring1 = Right, Ring2 = Microphone, Sleeve = Ground
Typical impedance (headphone output)	16–300 Ω (load); device output impedance typically <5 Ω
Maximum rated current (signal contacts)	Typically 1 A (contact manufacturer's datasheet for specific values)
Related standard	IEC 61076-3-104; IEC 61938 (audio interface); CTIA/AHJ specification

Safety warnings

Never use unbalanced 3.5mm TRS cables in locations where they may be exposed to mains voltage — for example, as a connection between consumer audio equipment and professional mixing consoles fed from different earth references. Ground loop currents can cause electric shock and equipment damage.
When cutting or stripping audio cable, use proper insulated tools and verify that the equipment connected at both ends is powered off. Unplugging a 3.5mm jack from powered audio equipment can cause transient pops that may damage speakers or hearing if volume is high.
The 3.5mm TRRS sleeve carries microphone signal in CTIA devices and ground in OMTP devices. Connecting a TRRS headset to the wrong standard device type will not cause personal injury, but it may disable microphone function and cause poor audio quality.
When soldering, work in a ventilated area and avoid inhaling flux fumes. Use appropriate eye protection when cutting wire or heat-shrink.

Tools needed

Soldering iron (25–40 W, fine tip)
Rosin-core solder (0.8 mm diameter)
Wire strippers (appropriate for fine audio cable gauge)
Digital multimeter (continuity and resistance modes)
Helping hands / third-hand soldering tool
Heat gun or lighter for heat-shrink
Magnifying glass or magnifying lamp (for fine TRRS contacts)

Common mistakes

Threading the housing onto the cable after soldering, necessitating complete desoldering to correct — always thread the shell first.
Using too much solder, creating a bridge (short) between the very closely spaced Ring and Sleeve contacts on a TRRS connector.
Connecting a TRRS headset to a device using the opposite standard (CTIA vs OMTP), then concluding the headset or device is faulty.
Forgetting to tin the cable conductors before attempting to solder them to the connector lugs, resulting in cold joints that fail intermittently.
Gripping the plug barrel in a vice and applying heat for too long, melting the plastic spacer and shorting adjacent contacts.

Troubleshooting

Left and right channels are swapped: Cause: Tip and Ring conductors are soldered to the wrong contacts, or cable is from a non-standard source with different colour coding Fix: Desolder and swap the Tip and Ring conductor connections. Retest with a known stereo audio source and verify left channel plays from the left earpiece.
Microphone not recognised or no mic input: Cause: CTIA/OMTP mismatch, TRRS headset plugged into a TRS-only socket, or open circuit on the mic conductor Fix: Try a CTIA-OMTP adapter. Verify the device socket is a TRRS type (four-contact). Use a multimeter to confirm continuity on the microphone conductor from plug sleeve/Ring2 to the mic capsule.
Intermittent audio dropout on one channel: Cause: Cold solder joint on the Tip or Ring contact, or internal conductor break at the stress point near the connector Fix: Flex the cable near the connector while monitoring the audio. If dropouts correlate with flexing, the fault is a fractured conductor inside the cable at that point. Reterminate the cable or replace the connector.

Frequently asked questions

What are the standard 3.5mm TRS contact assignments?

For stereo audio: Tip = Left channel, Ring = Right channel, Sleeve = Ground. This is universal for stereo headphones and aux cables. For balanced mono (professional applications): Tip = positive (hot), Ring = negative (cold), Sleeve = ground/shield. The same three physical contacts serve both applications with different wiring.

What is the difference between CTIA and OMTP TRRS pinouts?

Both standards assign Tip = Left, Ring 1 = Right. They differ in the last two contacts: CTIA uses Ring 2 = Ground, Sleeve = Microphone; OMTP uses Ring 2 = Microphone, Sleeve = Ground. Using a CTIA headset on an OMTP device results in no microphone function and noisy audio because ground and mic are swapped.

How can I tell if a 3.5mm jack is TRS or TRRS?

Count the dark insulating rings (bands) on the metal barrel of the plug. TRS has two rings (three contact segments — Tip, Ring, Sleeve). TRRS has three rings (four contact segments — Tip, Ring 1, Ring 2, Sleeve). Some adapters convert between them; a TRRS-to-TRS adapter simply omits the microphone connection.

Why does my headset microphone not work on my laptop or phone?

The most common cause is a standard mismatch (CTIA vs OMTP), a physical connector mismatch (TRRS headset into a TRS-only socket), or insufficient socket contact pressure. Try a small CTIA/OMTP adapter. On laptops, also check that the combined headphone/mic socket is set to headset mode (not headphone-only) in the audio driver settings.

What does a TS connector carry and how is it different from TRS?

A TS (Tip-Sleeve) connector has only two contacts and carries mono unbalanced audio — Tip = audio signal, Sleeve = ground. It is used for electric guitars, most instrument cables, and mono patch cables. It looks identical to TRS but has only one insulating ring. Plugging a TS cable into a TRS balanced output will short Ring to Sleeve, which most professional gear tolerates safely.

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