The 3.5 mm audio jack is one of the oldest connector standards still in daily use. It predates stereo audio by decades and has been extended multiple times to carry more signals through the same cylinder. Get the pinout wrong on a DIY cable and you end up with swapped channels, missing audio, a dead mic, or a phone that cannot detect the headset at all. This guide covers every common variant -- TS, TRS, TRRS -- and the two competing TRRS standards that are responsible for most headset compatibility headaches.
Connector Anatomy
The jack is named for its sections from tip to base:
- Tip (T) -- the very end of the plug
- Ring (R) -- one or more conductive bands separated by insulating rings
- Sleeve (S) -- the long cylindrical body at the base
Adding more rings adds more conductors. The sleeve is always ground in every variant.
TS (2-conductor)
Used for unbalanced mono audio: guitar cables, patch cables, mono instrument connections.
- Tip: Signal (mono audio or unbalanced hot)
- Sleeve: Ground/shield
TRS (3-conductor)
The standard stereo headphone connector.
- Tip: Left channel (audio hot, +)
- Ring: Right channel (audio hot, +)
- Sleeve: Common ground
TRS is also used for balanced mono audio in professional gear (tip = hot, ring = cold/return, sleeve = shield). Context -- consumer headphone vs. pro gear -- tells you which convention applies. A stereo TRS cable from a consumer headphone should never be plugged into a balanced mono input without understanding this difference.
TRRS (4-conductor)
Extends TRS with a second ring to add a microphone or combined mic/remote signal. Used on mobile headsets, earbuds with in-line controls, and headset jacks on laptops and phones.
- Tip: Left audio
- Ring 1: Right audio
- Ring 2: Ground (or microphone, depending on standard)
- Sleeve: Microphone (or ground)
Two competing pinouts exist for the last two conductors.
CTIA vs OMTP: The Headset Standard War
When smartphones started adding headset jacks, manufacturers could not agree on the ground/mic order:
CTIA (AHJ -- American Headset Jack)
Used by Apple (iPhone from 3GS onward), most Android phones after 2012, and essentially all current hardware.
| Segment | Signal |
|---|---|
| Tip | Left audio |
| Ring 1 | Right audio |
| Ring 2 | Ground |
| Sleeve | Microphone |
OMTP (Older Nokia, Samsung early models, some Chinese handsets)
| Segment | Signal |
|---|---|
| Tip | Left audio |
| Ring 1 | Right audio |
| Ring 2 | Microphone |
| Sleeve | Ground |
OMTP and CTIA swap the ground and microphone positions. Plugging an OMTP headset into a CTIA jack usually results in the mic being very quiet or completely silent while audio plays fine, because the microphone sees a low-impedance ground load instead of a bias voltage. The fix is a CTIA-to-OMTP adapter (a simple sleeve-to-ring-2 swap) or a headset that matches the jack.
For any new DIY build, use CTIA -- it is the current standard on every device made in the last decade.
Soldering a Stereo TRS Cable
A replacement or custom aux cable is a common maker project. The process applies to both 3.5 mm and 6.35 mm (1/4") TRS jacks.
Materials:
- TRS jack plug (metal body recommended over plastic for strain relief)
- Stereo shielded cable (two conductors plus braided shield)
- 25 W soldering iron, 60/40 or 63/37 solder
Steps:
- Slide the plug body and any strain relief sleeve onto the cable before soldering -- you cannot add them after the fact.
- Strip 20 mm of the outer jacket. Twist the shield braid together into a single strand.
- Strip 5 mm of insulation from each inner conductor.
- Tin all three wires and all three solder buckets on the jack.
- Solder the left conductor (typically red or marked) to the tip lug.
- Solder the right conductor (typically white or plain copper) to the ring lug.
- Solder the shield braid to the sleeve lug (ground).
- Inspect for solder bridges between tip and ring -- this shorts the channels and reduces output to a summed mono signal.
- Slide the body over and tighten.
One practical check: plug into a phone playing stereo audio and verify left channel (tip) plays audio in the left ear and right channel (ring) plays in the right ear. If channels are swapped, desolder and reverse the tip and ring connections.
Soldering a TRRS Headset Cable (CTIA)
TRRS plugs have three lugs instead of two, which requires careful planning because the third ring sits between the other two -- access is tight on small plugs.
Typical cable core colors vary by manufacturer; check continuity before soldering. For a headset cable with mic:
| Lug | Signal | Common Wire Color |
|---|---|---|
| Tip | Left audio | Red |
| Ring 1 | Right audio | Green |
| Ring 2 | Ground | Bare copper (shield) |
| Sleeve | Microphone | Blue or white |
Work in order from tip to sleeve. Apply the absolute minimum solder to avoid bridging. A flux pen helps solder flow on small lugs. Test continuity between all adjacent segments before assembling the body -- a solder bridge between Ring 2 (ground) and the mic sleeve will short the microphone to ground.
Breadboarding with 3.5mm Jacks
Panel-mount or PCB-mount 3.5 mm jacks are common in maker projects -- headphone amplifiers, audio mixers, guitar effects pedals. Most break out each conductor to a separate solder pin or through-hole pad. On a TRS PCB jack the pads are typically labeled T, R, S (or 1, 2, 3). On a TRRS jack look for T, R1, R2, S or similar labeling in the datasheet.
Useful in embedded audio projects:
- A TRS jack on an Arduino project can send stereo audio through a cheap DAC (e.g., PCM5102A).
- A TRRS input can capture microphone audio into a microcontroller's ADC (with appropriate biasing).
- You can draw and simulate the biasing resistor network for a microphone input in CircuitDiagramMaker before cutting traces.
Common Wiring Mistakes
Shorting tip to ring: Even a small solder bridge kills stereo separation or shorts the amplifier output. Check with a multimeter in continuity mode before assembly.
Confusing CTIA and OMTP: Building a headset cable with mic and guessing the standard. Identify your target device's pinout first.
Unshielded cable in audio applications: Omitting the shield on a line-level cable creates a noise antenna. The sleeve/ground must connect to the cable shield.
Floating ground on a balanced TRS misread as stereo: Connecting a balanced TRS output (tip = hot, ring = cold) into a stereo amp hums loudly and may damage the output stage.
Create Your Own Audio Jack Wiring Diagram
CircuitDiagramMaker makes it straightforward to document connector pinouts and audio routing:
- Draw TRS and TRRS connector symbols with labeled segments
- Map left/right/ground/mic paths through cables and PCBs
- Show biasing resistors and capacitors for microphone inputs
- Document CTIA vs OMTP configurations side by side for reference
Create your own audio jack wiring diagram -- free
Key Takeaways
- TS has two conductors (mono signal + ground); TRS adds a ring for stereo right channel; TRRS adds a second ring for microphone or ground.
- The sleeve is always ground on TS and TRS; on TRRS it carries the microphone signal in CTIA or ground in OMTP.
- CTIA (tip=L, ring1=R, ring2=GND, sleeve=MIC) is the current universal standard -- use it for all new builds.
- OMTP swaps Ring 2 and Sleeve; an CTIA headset in an OMTP jack will have no microphone output.
- Solder bridges between adjacent segments are the most common soldering fault -- check continuity before assembling the plug body.
- On PCB and panel-mount jacks, verify pad labeling against the datasheet; manufacturers use different label schemes.
Originally published at https://circuitdiagrammaker.app/blog/audio-jack-wiring-diagram.
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