Headphone Jack & Plugs | Types and Size Ideas Explained

Are you trying to fit a headphone jack in a smartphone, and it is not working as intended? Are you confused about its types and plug sizes? Don’t worry; you are not alone as many people don’t know about this simple information. This article will explain the headphone jack types and how it works to remove any confusion about this outdated but useful piece of tech.

You may be wondering why we have listed the headphone jack as an outdated tech. The Headphone jack is becoming an outdated tech, especially for smartphones, after Apple has discontinued it for its latest iPhone models. The upgrade from the headphone jack was simple; the newer Lightning connector can handle more data and process active noise cancellation.

Let’s not drift away from the primary topic as we are not here to explain the lighting connector. After reading this article, you can easily distinguish between headphone jack size and its different parts. We will explain the connector types (which is very easy to distinguish) and give you an overview of the diagram and anatomy of the headphone jack. Let’s get started!

headphone jacks plugs explained

What is a Headphone Jack?

A headphone jack transmits and receives audio signals in an electrical connector. We commonly call it audio jack, phone connector, and jack plug. It is an analog socket small, round, hollow, cylindrical shape. There are male and female ends for headphones functioning as jack acts as female connector while the plug acts as a male connector.

The headphone jack is present on most devices, while the male connector plugs usually come connected to the cord. The device has the jack transmit digital signals through it, and the connector converts these signals to analog for transmitting. When we connect the plug to the connector/jack, it completes the connection.

The signal transmitted through the plug reaches the other end, which we listen to from our earphones as audio. Most headphone jacks are capable of transmitting analog signals. However, exceptions like Google Chromecast, which transfers digital audio signals.

History of Headphone Jacks

Headphone jacks are not new to humanity. Their origin goes back to 1874. At the start, they were known for plugging and unplugging the connector for the manual calls. The most prevalent jack type was 6.35mm, which reduced over time.

History of Headphone Jacks

Later in the 20th century, the 3.5mm headphone jack was common. It became mainstream and spread widely due to its adaptability in the headsets on the transistor radios. However, another size was also introduced later on, known as 2.5mm jack, and it became mainstream in the 21st century. We will explain these types later in the article.

Headphone Jacks Plugs Explained

The appearance of the headphone plug and jack varies as one is male and the other is a female end. The headphone plug is round-shaped, having a chisel tip with a spring-loaded retainer for the jack to hold it. The mechanism is simple, and it does not need to be a scientist or engineer to understand.

A cord attaches to the headphone plug, making it possible to create an electrical circuit. Both headphone jack and plug have a conductor that provides a connection point for the circuit completion. The number of conductors can range from 2 to 5 numbers.

All headphone jack and plugs can look similar, but some functional difference makes them non-compatible with each other. Two things are more important for compatibility: headphone jack wiring diagram and size. There are two to five conductors on the headphone plug that act as the connectors. These conductors include a tip, ring, and sleeve.

We indicate the tip with “T,” Ring with “R,” and Sleeve with “S.” Out of these conductors, the tip acts as tip of the connector, ring separates the tip and sleeve, and the sleeve determines the diameter of the connector.

All headphone plugs come equipped with the tip and sleeve while the ring separates them. Dark color or black bands on the headphone plugs help keep the conductors separate and prevent any event of them being shorted together.

It is easy to understand the plug’s toponomy with the help of several rings present in them. These are the type of plug connectors:

  1. TS or 2 Conductors
  2. TRS or 3 Conductors
  3. TRRS or 4 Conductors
  4. TRRRS or 5 Conductors

It is the outer diameter of the sleeve conductor that determines the name of the plugs. All the rings and sleeve contacts have a similar diameter. If the plug sleeve diameter is ¼ inch, it is a 6.35mm plug. Similarly, the miniature sleeve diameters are 3.5mm, and the sub-miniature is 2.5mm.

Headphone Plugs Arrangement

Headphone Plugs Arrangement

Different types of phone connectors have a different arrangements. In this section, we will focus on the available plugs arrangement.

1) TS or 2 Conductors Plugs

Audio signals get transmitted via a two-conductor plug. The plug’s tip is where amplified sound originates, while the sleeve serves as a ground and return path for the audio signal.

The TS connectors are fairly straightforward, with only two conductors. The first one servers the purpose of an audio signal, and the other carries and handle the ground and return path. Since the audio signal in the TS connectors travels in one direction, the signals it carries are unbalanced mono audio.

TS conductors are rare in the headphone jacks as they are native to 2.5mm connectors. They are also present in the instrument cable with 6.35mm connectors. If you are a musician or play guitar in your free time, you probably use these plugs for connecting an electric guitar to the amplifier.

2) TRS or 3 Conductor Plugs

TRS connectors are the most common plugs found in headphones. When people refer to a 3.5mm plug, they mean these plugs because they have three conductors. One of those is a return path and ground, while the other two serve as the left and right audio channels.

TRS or 3 Conductor Plugs

Typically, cables with this type of plug are distinct as they can only handle unbalanced stereo signals. They carry the left and right audio signals separately rather than mixed. TRS connectors are prevalent in the 6.35mm and 3.5mm plugs but are commonly used with 3.5mm plugs.

The TRS cables are different from TS cables as they can carry balanced mono audio signals. The ring and tip and revered polarities carry the same audio signal. However, for headphones, the mechanism is different.

Besides the balanced mono audio, the TRS cable can transfer and carry an unbalanced mono connection. The ring in this headphone plug transfers the microphone signal. However, you won’t find these headphones more often for daily use.

3) TRRS or 4 Conductor Plugs

TRRS conductors have another ring added to the schematic and are prevalent in the headphones. They help to transfer the unbalanced stereo signals, and it still has the conductor left that can handle the microphone function efficiently.

There are two common arrangements in the TRRS: OMTP (Open Mobile Terminal Platform) and CTIA (Cellular Telecommunications and Internet Association). Things here start to get tricky regarding each conductor’s role in the signal transfer.

OPTP is the older standard that utilizes the common return wire and ground for the sleeve conductor. In contrast, the CTIA utilizes the sleeve for handling the microphone audio wire.

You can use the TRS plug without any issues with the jack TRRS. However, to work them and bypass the compatibility issues, you need to insert the plug into the jack of the same diameter while retaining the identical wiring schematic. Most TRRS jacks on the smartphone still have a 3.5 mm jack to handle the microphone signal and let the functions work proficiently.

That said, not all headphones have a built-in microphone. Most headphones do not come with a built-in mic. If they don’t have a microphone, they will use a TRS plug. There are variations of the CTIA standard used to keep the same conductor arrangement between TRRS and TRS plugs relative to the signals these conductors carry.

The basic functioning remains the same as the tip carriers of the left audio signal. The right audio signal gets transmitted using the ring adjacent to the tip. For the TRS plugs, a sleeve is present that handles the ground and return path.

The compatibility between the TRS and TRRS jacks depends on the second ring that servers as the ground and return path. All this gets accomplished through the CTIA standard. The TRRS plugs are prevalent with headphones that have a microphone.

TRRS jacks compatibility is vast, and it extends to all the devices that support both stereo audio and microphone, including gaming consoles and smartphones. However, the conductors of these devices have the wiring schematics according to the CTIA standards to make them compatible with the headphones that lack microphones.

4) TRRRS or 5 Conductor Plugs

TRRS connectors are unique according to their functioning, supporting balanced stereo signals. The wiring schematics, in most cases, allow the sleeve to serve as a ground. It lacks the return wire. The sleeve has two adjacent rings that transfer the right audio signals and carry hot and cold audio channels. The tip and remaining ring carry the left channel audio signals and carry hot and cold channels.

The audio signals split into two hot (positive) and cold (negative) channels. They pick the same interference when catching the signals. However, the signals of the cold channels reversed once they reached the end of the cable.

It helps flip the audio channels and return them to positive while turning the interference into negative. Then, the negative and positive instances of the same signals try to minimize and cancel each other to provide a path for clean signals. It is the famous method known as CMR (Common Mode Rejection) for interference elimination.

TRRRS or 5 Conductor Plugs

It means that if the second channel does not undergo the flipping a second time, the negative and positive signals can cancel each other. You won’t hear anything besides the interference because both the signals are positive. Although it is impossible, it helps differentiate the difference and understand the principle behind CMR.

Now, returning to the TRRRS connectors, these plugs are destined for devices that need sound clarity and are oriented towards audiophile-grade devices. However, to serve the purpose of the headphones, XLR connectors are more common than the TRRRS for supporting balanced stereo connections for listening clarity.

Several manufacturers are working on the TRRRS headphone jack and calling the 4.4mm connectors. However, only Sony released these TRRRS headphone jack with the Pentaconn connectors. Besides the Sony products, we have not seen many implementations of the TRRRS balanced headphones, but it is finally something big that will happen in the next few years for audiophiles.

How Do Headphone Jacks Connect?

Like any peripheral for computer or electronic devices, headphones also need compatibility. However, this compatibility varies for what functions you want from the device. Two attributes contribute to the functioning of a headphone jack and plug to work correctly.

  • Similar wiring schematic
  • Same headphone jack size

As you already understand that headphones are not digital devices. They work on analog principles. The signals that transfer through the analog signals are AC voltages. These signals get transferred through a conductive medium of the wires. Each wire in the cable attaches to the cable plug. Even the jack source has conductors that deliver the signals specifically.

The jack needs to connect with the plug conductors to let the audio signals flow through the cable. Wiring schematics help transfer the flow of the signals from the headphone plug and jack. If the schematics are not the same, the plug won’t transfer the signals as the conductor lacks the contact.

We cannot see the physical connection between the plug and jack. However, understanding the headphone jack and plug types and their compatibility can help us to understand which jack can work with which plug. The next section will help you to understand this basic concept.

Headphone Jack and Plug Compatibility

The headphone plugs and jack show the same wiring schematic compatibility. However, there are certain instances that the headphone jack and plugs remain compatible even with some differences in the conductors and size. Some headphone jacks and plugs may not match up even having the same size.

A headphone with a mic and 3.5mm TRRS plugs that’s built-in according to CTIA will be compatible with any 3.5mm TRRS jack as they all make use of the same wiring schematic and have identical proportions same size/shape.

Also, suppose you happen to be using a 3.5 mm TRS stereo headphone plug into a 3.5 mm TRRS balanced jack. In that case, it will work perfectly fine as the sleeve used to carry the microphone signal on the TRRS jack happens to be grounded and matches up with the TRS plug of the headphone. Additionally, the ground wire meant to connect both parts works as well.

Connecting a TRRS headphone jack using the CTIA standard to a TRRS headphone plug using the OMTP standard will not work. The reason is that you have exchanged the common return and mic signals, and they contain different signals, which makes this compilation incompatible as even if both connectors have the same size and fit together, it still won’t work.

While standard headphone jacks generally come in one shape and size, having a headphone jack adapter on hand can be useful. The 3.5 mm to 6.35 mm is among the most common ones as some devices still use this input standard.

You can find many DIY connectors and adapters for your needs with high-quality cables readily available for purchase online at Amazon. Apple users can use a headphone jack to lightning adapter for their iOS devices. Even a headphone jack splitter connects the headphone with two plugs to the 3.5mm jack on smartphones and other audio devices.

Headphone Jack Sizes

Headphone Jack Sizes

This section is self-explanatory as we will discuss headphone jack sizes. Everyone is familiar with the 3.5mm jack, but most people don’t know that three more headphone jacks are widely used in different devices. All these have jacks have different sizes while their working principle remains the same.

Here is the list of headphone jacks:

  • 6.35 mm
  • 4.4 mm
  • 3.5 mm
  • 2.5 mm

1) 6.35 mm

It is the largest headphone jack, commonly known as ¼ inch connector. These jacks are used in headphone amplifiers and digital to analog converters (DAC). It also happens to be most notable for its inclusion on the well-known Schiit Mjolnir 2, which uses both a 6.35 mm jack and an XLR port.

2) 4.4 mm

Although they’re missing some clarity in other balanced headphone jacks, they can still provide an excellent audio experience. Most notably, 4.4-mm headphone jacks are primarily used in professional and telecommunication settings due to their compatibility with specific devices. Several examples of a digital audio player equipped with this particular jack size.

3) 3.5 mm

It is commonly known as a mini-jack due to its ¼ inch size. Besides its size, it is the most common type of jack available. Its usage extends to portable players, laptops, and smartphones. Recently Apple has removed the headphone jack from its smartphones in iPhone 7. It caused a stir in the smartphone industry, but still, it is the most prevalent headphone jack type that remains the bread and butter of the audiophiles who prefer high-quality sound without latency issues.

4) 2.5 mm

It is the smallest of all and named as sub-mini and sub-miniature connector. It is also famous for the name 2.5 mm micro-jack. Further types are associated with the 2.5mm connector, but they are fading as more and more manufacturers are interested in the 3.5 mm or mini-jack for their devices.

Final words
While all this information about the headphone jack and plugs may seem overwhelming for most readers, we tried to explain everything in a manner that you can understand without any confusion. You got to know about the basics of the headphone jack, its history, types, and diagram.

You can easily understand the working of the headphone jack. The different adapter types and sizes can confuse, but we have made it clearer to understand. You can easily decipher the working of the plug and jack to understand which is better for your device.
How to connect the headphone jack to USB on a computer?

Headphone jacks are not compatible with the USB directly. However, you can use 3rd party connectors to connect the headphone jack to the USB. Many headphone jack to type C connectors available on Amazon offers you the functionality to connect the 3.5mm jack with the USB using a converter.

What is the standard headphone jack size?

Headphone jacks come in different sizes ranging from 6.35mm to 2.5mm. However, the standard headphone jack size for most smartphones and audio devices is the 3.5mm headphone jack. It is a more prevalent type that we see on every second device we use.

Can we use a 3.5mm headphone jack adapter with USB input?

Yes, using the 3.5mm headphone jack adapter with the USB input is possible. Many manufacturers offer this utility to make it possible to use the old 3.5mm headphones with the newer devices requiring the USB input for the headphones.


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