What is an Auxiliary Port (AUX) and what’s it for?

What is an Auxiliary Port (AUX) and what’s it for

What method do you use in listening to music in the car while driving? Some people use CDs, radios, car navigation HDD drives, SD cards, etc. Actually, there are quite a few people who use the AUX port of their smartphones.

Therefore, here I will focus on how to listen to music using AUX port.

Admittedly, it is possible to use Bluetooth to connect the smartphone with the car radio, but the AUX port remains the solution most used by drivers. Admittedly, the port is absent from the latest Apple devices, but it is present in millions of mobile devices around the globe. But what is an auxiliary (AUX) port and what is used for? 

What is an Auxiliary Port?

An auxiliary port (AUX) is the logical name for a standard communications port. AUX is an asynchronous serial port with an interface that allows the auxiliary input of audio signals for MP3 players, Headphones, Portable music players, Amplifiers, Speakers.

Or simply put, the auxiliary port (AUX) is a socket that is most often found on car radios and is used to connect an external walkman, a smartphone or a tablet via a cable. Thus, the driver can listen to music stored on his device directly on the speakers of his vehicle.

What you can do with the AUX terminal

So what can you do with a terminal that conforms to this AUX standard? When considering a car audio sound source, I think of using a standard radio or CD as the sound source, but if it has an AUX port, connect an external input terminal such as a smartphone with a stereo mini-jack plug. You will be able to.

Therefore, you will be able to play music files saved on your smartphone on your car stereo.

Smartphones, which have become popular in the last few years, can play their favourite songs with a music-only app, so you can freely listen to the music files with car audio.

How to connect a car stereo and a smartphone

Now, let’s explain how to connect a car stereo to a smartphone.

To connect with a plug that supports the AUX port and listen to music, connect a smartphone terminal such as android or iOS to the AUX out terminal and the AUX in port of the car audio with a mini-plug cable.

The second side of the adapter must match the connector of the phone, smartphone, tablet or laptop. This small wire will allow you to connect your portable device to your car for the seamless transfer of any audio files.

However, as for the out port of the smartphone, a mini-jack (3.5 mm) is supported unless it is a model after Xperia XZ2 of android or a model that does not support AUX such as iPhone8 / iPhone X and after.

AUX connector features

AUX input on car dashboard.

The AUX connector is a small round hole with a diameter of 3.5 millimetres. It freely accepts a plug with a configuration of a figured metal rod, as for ordinary headphones.

In expensive cars, the AUX connector is mounted next to the cigarette lighter or radio and is closed with an outer cover that prevents moisture and dust from getting inside the recess. The presence of an entrance saves the car owner from the need to equip the interior with a multifunctional radio tape recorder and makes it possible to use not only the resources of the connected electronic media but also play music from the internet.

Why is it convenient?

  • The technical functions of conventional radio tape recorders are significantly expanding.
  • You can listen not only to your favourite music but also broadcasts from virtual radio stations.
  • Additional connection of absolutely any external devices is possible.
  • No financial investment is required to update the built-in car audio systems.
  • Broadcasting sound through a phone connected to the AUX input will be no worse than the quality of the reproduced music from a flash drive or disk.

DIY AUX input

If your car and the radio built into it do not have an AUX connector, then if you wish, you can install it yourself. In the absence of technical skills, you should order a service from a specialist at the service station.

To mount the AUX jack, you will need three small wires forty, fifty centimetres long with a small cross-section. They will need to be soldered to the stereo output channels from the player to the main device. After that, the wires are brought out and a socket for an audio connector with three pins is attached to them. The AUX connector itself is fixed in a convenient place for use on the dashboard or directly on the radio.

With a certain experience and the availability of the necessary tools, the work will take about an hour and a half. And consumables will cost a penny. But at the end of the installation process, even in the most budget or old car, you can listen to music, audiobooks, online broadcasts.

Things to be careful about when connecting a car stereo and a smartphone

In order to connect your car stereo to your smartphone and enjoy music, you should be aware of the following points.

The first is to disable the sound quality adjustment function of your smartphone.

If the sound quality can be adjusted on both the smartphone and the audio, the control will be doubled and the operation will be troublesome. Therefore, by narrowing down the volume control to the audio side, it becomes easier to adjust with a simple operation.

Next is to maximize the volume of your smartphone. If you use the AUX terminal to link your smartphone to stereo, the noise will increase.

This makes it difficult to listen to the content, but by setting the volume of the smartphone to MAX, the ratio will be low even if noise is mixed in, so you will not be bothered.

What are the advantages of AUX over Bluetooth?

Hands-free calls: Connecting an intercom (in our case, a phone) to the stereo system via an auxiliary physical connection completely eliminates the possibility of making external calls.

And this is that many of the phones on the machine are connected to a wired connection in order to process any incoming or outgoing calls if a wired connection is present.

Of course, as usual, it leads to a situation where the interlocutor speaks while being on the other end of the wire through the speakers of the music centre, but the interlocutor is out of the hearing zone.

Hassle-free connection: When the phone is connected to the stereo system through the AUX port or information portal, the main purpose is to listen to music files.

However, creating this type of connection also provides access to voice calls. No need to bother with setting up a separate connection or fiddling with a wireless stereo headset.

Working with Bluetooth to stream music files is the best way to avoid this kind of problem because the phone and car stereo usually switch from the music streaming profile to the bonding profile at the time of a phone call.

Fast and easy: A clear advantage over a car AUX port is that setting up an AUX connection, while a little finicky, is a more convenient and easier process.

After establishing a connection between two devices, you can add the gadget to your phone’s Trusted Device list, and then you do not need to repeat this process again.

Bluetooth or auxiliary. What is the best fit for your car?

Like so many things in life, there is no easy answer to this. Each audio connection technology has its own strengths and weaknesses, which means it is suitable for certain purposes.

If you are looking for the most convenient way to do business in a car. You can’t beat Bluetooth because it provides a fast, easy way to do it. If you are looking for versatility for the price and good music quality, AUX is the best option.

What is a DAC and why does it matter?

In the world of audio, a DAC is a digital-to-analogue converter. This is a technology that you probably use on a regular basis, but you never have to think about it. Your smartphone, MP3 player, stereo system and many other devices contain a DAC.

In basic terms, a DAC takes digital data and turns it into an analog signal that can then drive speakers or headphones. Whenever you listen to a CD on your stereo or listen to an MP3 on your phone, the DAC must take the digital information and process it into an audio signal.

While the aux inputs and USB are good ways to connect your phone or MP3 player to your car stereo, there can be a huge difference in quality based on a DAC. This is because the Aux connection uses the DAC in your phone or MP3 player, while the USB connection allows the DAC in your car stereo mode to process data located on your phone or MP3 player.


Please enter your comment!
Please enter your name here