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3.5mm Audio Jack Basics

The audio jack was invented in the 19th century and is used in telephone switches. It is still widely used to transmit analog audio signals.

What is 3.5mm Audio Jack

Today, 3.5mm is the universal audio jack size found in smartphones, PCs and laptops. In addition, for amateurs, the 3.5mm audio jack is a useful component of the project that plugs into the headphone jack. There are different types of 3.5mm audio jacks available for different applications such as TS, TRS and TRRS, but the most common ones in our daily life are TRS and TRRS.

3.5mm Audio Jack
3.5mm Audio Jack

3.5mm Jack Datasheet

3.5mm Jack Pinout

The pinout configuration is as the following table:

Pin No.Pin NameDescription

3.5mm Jack Types

There are 3 types of 3.5mm Jack here:

  • TS Type Male Audio jack
  • TRS Type Male Audio jack
  • TRRS Type Male Audio jack

TS Type Male Audio jack

These types of audio jacks do not support stereo and microphone, which means there is no left or right. Both parties will receive the same voice. Below is the pinout for the TS male audio jack. TS type male audio jacks are mainly used for music equipment (especially electric guitars) and aeronautical radios.

TS Type Male Audio jack
TS Type Male Audio jack

TRS Type Male Audio jack

Here, in the name of TRS, “T” stands for Tip, “R” stands for Ring, and “S” stands for Sleeve. These types of audio jacks support stereo but do not support microphones. Therefore, with this feature you can only listen to music and not talk. Below is the pinout of the TRS male audio jack. Their range of applications is speakers, microphones, keyboards, etc.


TRS connector typical pinout for audio plug is as the following table:

NamePositionNumberMost common Colour
L (Left Signal)Tip1Green
R (Right Signal)Ring2Red
GND (Ground)Sleeve3Bare Copper

TRRS Type Male Audio jack

The TRRS audio jack has four wires and is the most popular on smartphones and tablets. The TRRS-type audio jacks are in the order of Tip-Ring-Ring-Sleeve and include stereo and microphone functions. There are many standards to use when making these audio jacks, such as OMTB and CTIA. This is why your smartphone does not support other brands of headphones. Below is the pinout of the TRS male audio jack. It is used in headphones of many brand companies, such as Apple, Nokia, Samsung, Panasonic and so on.


How to use the audio jack

To use a 3.5mm audio male hole in a project or prototype, you must use the pin of the hole to solder the wire. Remove the plastic case from the top and you will see the jack pins as shown above. Now, use multiple strands to solder with the pins and then cover them again with a plastic case.

3.5 mm-Audio- Jack-circuit-diagram
3.5 mm-Audio- Jack-circuit-diagram

Some common uses of jack plugs and their matching sockets

  • Headphones and headphone jacks on a variety of devices. 1/4″ plugs are common on household and professional component devices, while 3.5mm plugs are common on portable audio devices. 2.5 mm plugs are not common, but can be used for communication devices such as cordless phones, mobile phones and two-way radios.
  • Consumer electronics devices such as digital cameras, camcorders and portable DVD players
  • Microphone input on tape and cassette recorder.
  • electric guitar. Almost all electric guitars use a 1/4-inch mono jack (socket) as an output connector.
  • Personal computers, sometimes using a sound card that plugs into your computer. 3.5mm stereo jack for: line input (stereo), line out (stereo), headphone/speaker output (stereo), microphone input.
  • A musical instrument amplifier for guitars, bass, and similar amplified instruments.
  • Step switch and effect pedal.The effect loops, usually connected as jumper points.
  • Line output.
  • The electronic keyboard uses the jack for similar uses of guitars and amplifiers.
  • Press the pedal.
  • Expression pedal.
  • The electronic drum uses a jack to connect the sensor pad to the synthesizer module or MIDI encoder. In this usage, the voltage change on the wire represents the drum sound.
  • Some small electronic devices, such as audio tape players, especially in less expensive brackets, use a two-core 3.5 mm or 2.5 mm jack as a DC power connector.
  • Modular synthesizers typically use a mono cable to make patches.
  • Some studio strobe lights.
  • Some cameras (such as Canon, Sigma, and Pentax DSLR) use a 2.5 mm stereo jack as a connector for remote shutter release (and focus activation); for example, Canon’s RS-60E3 remote switch and Sigma’s CR-21 wired remote.
  • Some small electronic devices use 2.5 mm or 3.5 mm jack plugs as serial port connectors for data transfer and unit programming. Apple’s second-generation iPod Shuffle has a TRS jack that can be used as a headset, USB or power source depending on the plug it is connected to.
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