TRS / TRRS phone plug pinout
TRS & TRRS Pinout (1/4" and 3.5 mm)
A TRS plug has three contacts: tip, ring, sleeve. For balanced audio the assignment is tip hot (+), ring cold (−), sleeve ground; for stereo headphones it is tip left, ring right, sleeve common. TRRS adds a second ring for headset microphones.
| Pin | Signal | Notes |
|---|---|---|
| Tip | Hot (+) / Left | Balanced hot leg, or left channel on stereo assignments. |
| Ring | Cold (−) / Right | Balanced cold leg, or right channel on stereo assignments. |
| Ring 2 (TRRS) | Mic or ground | CTIA: sleeve = mic, ring 2 = ground. OMTP (older): swapped. |
| Sleeve | Ground / mic (TRRS) | TRS shield and signal common. On TRRS, CTIA uses the sleeve for mic; OMTP uses it for ground. |
What it’s used for
Quarter-inch TRS covers three unrelated jobs on stage: balanced line interconnects (tip/ring/sleeve as +/−/ground), stereo headphone feeds, and console channel inserts where one jack carries send and return.
The 3.5 mm TRRS on phones and laptops follows the CTIA assignment on essentially all modern devices: left, right, ground, mic from tip to sleeve. Legacy OMTP devices swapped the last two, which is why an old headset’s mic hums or mutes on modern hardware.
Wiring & termination notes
- A TS (two-contact) plug in a balanced TRS input shorts the cold leg to ground: it works, unbalanced, at 6 dB lower level. Intentional for guitars, accidental everywhere else.
- Insert jacks are commonly tip = send, ring = return (Mackie and most modern consoles), but the reverse exists on older desks; the console manual wins.
- Balanced TRS-to-XLR: tip to XLR pin 2, ring to pin 3, sleeve to pin 1.
- TRRS breakout adapters must match CTIA; adapters for OMTP exist and look identical. If the mic does not pass, suspect the standard before the headset.
Frequently asked questions
Is TRS balanced or stereo?
The connector supports both and the context decides: a TRS patch between console and processor is balanced mono; a TRS into a headphone amp is unbalanced stereo. The wiring is identical, the interpretation is not.
What is the difference between CTIA and OMTP on TRRS?
The last two contacts swap: CTIA (modern standard) puts ground on ring 2 and mic on the sleeve; OMTP reverses them. A mismatched headset gives weak or no mic and sometimes muffled audio.