4 Pole Headphone Jack Wiring Diagram (TRRS: CTIA vs OMTP)
This is a free printable 4 pole headphone jack wiring diagram: download the diagram as SVG or open it and print to paper or PDF.
A 4 pole headphone jack wiring diagram covers the TRRS connector — Tip, Ring 1, Ring 2, Sleeve — and the two competing pinout standards: CTIA (used by Apple and Android) and OMTP (legacy standard).
A standard 3.5 mm audio jack has three conductors: Tip (left audio), Ring (right audio), and Sleeve (ground). Adding a fourth conductor — a second Ring — creates the TRRS (Tip, Ring, Ring, Sleeve) connector used in headsets that combine stereo audio with a microphone and in-line controls.
The problem is that two incompatible pinout standards exist for that fourth conductor, both using the same physical 3.5 mm 4-pole plug and socket.
CTIA (also called AHJ — American Headset Jack — or the 'Apple standard'): Tip = Left audio, Ring 1 = Right audio, Ring 2 = Ground, Sleeve = Microphone. This is the standard used by Apple iPhones (prior to iPhone 7), the vast majority of Android devices from 2010 onwards, and most modern consumer electronics.
OMTP (Open Mobile Terminal Platform — a legacy standard popular in Nokia, early Samsung, and Sony Ericsson handsets): Tip = Left audio, Ring 1 = Right audio, Ring 2 = Microphone, Sleeve = Ground. Note that the Ground and Microphone positions are swapped relative to CTIA.
Connecting an OMTP headset to a CTIA device produces audio but no microphone function (or a microphone that picks up nothing), because the device is applying microphone bias voltage to what is ground on the headset. The left and right audio and the ground reference are different enough that you will typically still hear sound, but the microphone circuit will not work correctly. Using a CTIA headset on an OMTP device produces the same mismatch.
Active CTIA-to-OMTP adapters (small passive inline adapters) simply swap the Ring 2 and Sleeve connections physically to convert between standards. No active circuitry is required — it is purely a wiring swap.
For DIY headset wiring: identify the device's standard first. Check the device specification or test with a known-good headset. Then wire accordingly.
How to wire 4 pole headphone jack wiring diagram
- Identify the target standard (CTIA or OMTP) Determine the pinout standard of the device you are wiring for. For CTIA (most modern devices): Tip = Left, Ring 1 = Right, Ring 2 = Ground, Sleeve = Microphone. For OMTP (legacy): Tip = Left, Ring 1 = Right, Ring 2 = Microphone, Sleeve = Ground. Document this before cutting any cable.
- Prepare the cable and thread the jack housing Thread the outer housing, strain relief boot, and any spring or collar onto the cable before stripping — it is impossible to add them after soldering. Strip the outer jacket to expose 20–25 mm of inner conductors. For enamelled (magnet wire) conductors, remove enamel by burning with a lighter or sanding with fine abrasive paper, then tin with solder.
- Identify each conductor Use a multimeter in continuity mode to map each inner conductor to each segment of a known reference jack or use colour coding if confirmed. Mark each conductor: Left (Tip), Right (Ring 1), Ground (Ring 2 for CTIA / Sleeve for OMTP), Microphone (Sleeve for CTIA / Ring 2 for OMTP).
- Solder Sleeve cup first Solder the ground conductor (CTIA) or microphone conductor (OMTP) to the Sleeve (barrel) solder cup. Apply heat to the cup, not the wire. The Sleeve is the largest solder point and the most robust; it is also the first to receive mechanical strain. Ensure a smooth, shiny joint with no excess solder.
- Solder Ring 2, Ring 1, and Tip in sequence Working inwards from Sleeve to Tip, solder Ring 2 (microphone for CTIA, ground for OMTP), then Ring 1 (Right audio), then Tip (Left audio). Inspect each joint before moving to the next. Keep solder amounts minimal — excess solder on Ring joints can bridge to the adjacent ring and cause crosstalk or shorts.
- Test continuity and isolation before assembling Before closing the housing, use a multimeter to verify: (a) continuity from each conductor to its correct plug segment, and (b) no continuity between any two adjacent segments. A bridge between Tip and Ring 1 shorts left and right channels; a bridge between Ring 2 and Sleeve shorts ground and microphone, potentially damaging the microphone bias circuit in the device.
- Assemble strain relief and test Slide the strain relief boot over the solder joints and tighten or heat-shrink as required. Assemble the outer housing. Test the completed cable with the target device: verify left and right audio independently (use a mono test tone or audio test application), then test microphone function by recording a voice note and confirming audio quality.
Specifications
| Connector standard | 3.5 mm (1/8 inch) 4-pole TRRS (Tip, Ring, Ring, Sleeve) |
|---|---|
| CTIA pinout (Tip to Sleeve) | Left audio / Right audio / Ground / Microphone |
| OMTP pinout (Tip to Sleeve) | Left audio / Right audio / Microphone / Ground |
| Microphone bias voltage (typical device supply) | 1.8–3.0 V DC through bias resistor (typically 2.2 kΩ) |
| Headphone impedance (typical consumer) | 16–600 Ω |
| Microphone element impedance (MEMS/electret) | Typically 200 Ω–2 kΩ |
| Applicable standard (CTIA/AHJ) | CTIA Headset Standard (AHJ), compatible with IEC 61938 (audio connectors) |
| Physical plug diameter | 3.5 mm; plug body length: short (3-ring visible at entry) vs standard |
Safety warnings
- This diagram is for reference and educational purposes only. Headphone jack wiring is low-voltage and not a safety-critical electrical hazard in itself, but soldering requires precautions: work in a ventilated area, avoid inhaling solder fumes (use an extraction fan or at minimum work away from the solder plume), and never touch the soldering iron tip.
- Verify the pinout of the target device before wiring. Incorrect wiring does not damage the device in most cases but can cause microphone malfunction. In some devices, sustained incorrect microphone bias loading could stress the bias circuit — verify before extended use.
- Do not use a TRRS audio jack for any application other than audio signal level voltages (typically less than 2 V peak). The physical connector is identical to some connector types used for different purposes — confirm the application before inserting.
- Solder joints on small audio connectors are mechanically fragile. Always apply strain relief to the cable before use. A cable with no strain relief that is regularly flexed at the plug will fail at the solder joint, potentially short-circuiting adjacent rings and producing a loud pop through the headphones.
Tools needed
- Soldering iron (temperature-controlled, fine tip, 20–30 W) with temperature set to 320–350 °C
- Solder sucker or desoldering braid for rework
- Digital multimeter (continuity, resistance)
- Wire strippers matched to conductor gauge (28–32 AWG)
- Fine-tip tweezers or helping hands for holding small components
- Heat gun or lighter for heat shrink tubing
- Magnifier or illuminated magnifying glass for inspecting small solder joints
- Solder flux pen or liquid flux for improved solder flow on fine conductors
Common mistakes
- Assembling the jack housing and strain relief after soldering — once the housing is on it is impossible to remove without cutting the cable.
- Confusing CTIA and OMTP pinouts and wiring microphone to ground position, resulting in absent microphone function and no obvious cause visible from the wiring.
- Bridging adjacent ring solder cups with excess solder, short-circuiting adjacent audio channels or grounding the microphone conductor.
- Failing to remove enamel insulation from magnet wire conductors before soldering, causing a dry joint that has electrical continuity only under mechanical pressure — it passes the bench test but fails within hours of flexing.
- Using the wrong solder — acid-flux solder intended for plumbing corrodes fine audio connectors. Always use rosin-core electronics solder.
- Not testing polarity of left and right channels after wiring — swapped left and right audio channels are not immediately obvious and cause disorientation during stereo listening, particularly for recorded spatial audio.
Troubleshooting
- Microphone does not work after wiring, but audio is correct
- Cause: Microphone conductor is wired to the wrong ring position — CTIA vs OMTP mismatch — or there is an open solder joint on the microphone conductor Fix: Verify the pinout standard of the device. Measure continuity from the microphone conductor to the Sleeve (CTIA) or Ring 2 (OMTP) of the plug. Reflow or redo the solder joint if continuity is absent. If the pinout was wired correctly, the device microphone bias circuit should be tested on a known-good headset to rule out device fault.
- Audio is present in only one ear
- Cause: Open solder joint on Tip (Left) or Ring 1 (Right) conductor, or a broken conductor in the cable Fix: Measure continuity from the suspect conductor at the plug Tip or Ring 1 to the headphone driver on that side. Reflow or rewire the open joint. If the cable conductor tests open, the cable requires replacement.
- Loud buzzing or hum in the audio, worse in the microphone channel
- Cause: Ground conductor poorly terminated (high resistance at the Sleeve solder joint), solder bridge between Ring 2 and Sleeve, or absence of shielding on a long microphone cable run Fix: Inspect and reflow the Sleeve (ground or microphone) solder joint. Check for solder bridges with a multimeter between all four segments. For long cable runs, ensure the cable has a braided or foil shield connected to the ground segment.
Frequently asked questions
How do I tell whether my device uses CTIA or OMTP pinout?
Check the device manufacturer's specification. Most smartphones and laptops manufactured from 2012 onwards use CTIA. Older Nokia, early Samsung, and Sony Ericsson devices typically used OMTP. If in doubt, plug in a known CTIA headset: if audio works but the microphone does not, the device is likely OMTP. A cheap CTIA-to-OMTP adapter confirms the diagnosis.
Will an OMTP headset damage my CTIA phone?
No — the pin mismatch is not damaging to either device or headset. The microphone bias voltage applied to the OMTP ground pin is typically 2–3 V DC at very low current, insufficient to cause damage. You will simply get incorrect or absent microphone function and possibly reduced audio quality due to the ground being routed through the microphone bias circuit.
What are the conductor colours inside a TRRS cable?
There is no universal colour standard for TRRS cable internals. Common schemes include: Red (Right), Green (Left), Copper or bare (Ground), Blue or White (Microphone). Some cables use a four-colour scheme; others use copper-coloured conductors with coloured enamel. Always verify with a multimeter — measure continuity from each conductor to each plug segment rather than relying on colour alone.
Can I wire a TRRS jack for balanced audio instead of microphone?
Yes, but only in applications specifically designed for 3.5 mm balanced output (some portable headphone amplifiers and DAPs use TRRS for balanced stereo: Tip = Left+, Ring 1 = Right+, Ring 2 = Left−, Sleeve = Right−). This is an entirely different application from the headset microphone wiring. Never assume a TRRS socket is wired for balanced audio without confirming the source specification.
How do I solder a TRRS 3.5 mm jack without bridging contacts?
Use a 3.5 mm jack with solder cups rather than tabs, and strip only 3–4 mm of insulation per conductor. Tin each cup and each conductor separately before joining them. Work in order from sleeve to tip — the sleeve cup is largest and easiest. Use a fine-tip soldering iron at 320–350 °C and apply heat for no more than 2–3 seconds per joint. Inspect with a magnifier for solder bridges between adjacent cups before assembling the strain relief.
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