The main reason many car audio systems are now equipped with USB port is to simply add another type of input. USB has become or is less common in all kinds of electronics, including cell phones and MP3 players, so it only makes sense for OEMs and aftermarket manufacturers to adopt this standard.
This means you can use the USB port on the head unit to play music from your phone, MP3 player, or even USB stick, as long as there are no compatibility issues. You can also charge your phone or turn on an additional device such as portable GPS Navigation Device, if supported by your head unit.
The main reason why car radios use USB
USB, in many of its incarnations, has more or less become the de facto way to connect electronic devices to other electronic devices and computers, which is perhaps why many automakers and aftermarket car audio manufacturers have chosen to use it instead of proprietary connections. Some car audio systems still use proprietary connectors, but you are more likely to find USB port in your new car stereo.
While USB connections can be used for firmware updates, charging and powering devices, and other less common scenarios, the main reason car audio systems use USB is as an alternative way. playing music and other audio content .
In some cases, especially older head units, the USB connection will simply act as alternative auxiliary input . This type of head unit allows you to play music from your phone or a dedicated MP3 player, but the car radio itself does not contain DAC or software capable of playing your music files.
Most car radios equipped with USB connectors also contain the necessary software or firmware to decode and play music files. If you have this type of head unit, you can plug in a cell phone, MP3 player, USB drive, or even a USB hard drive (provided it has a power source) — and play music directly from that device.
Listening to music via USB car audio
Every head unit is different, so you may need to play around with the options or even read the manual if you want to listen to music over a USB connection. In an ideal world, you can simply plug in an MP3 player or media with music files on it, the head unit will recognize it, and your music will play. However, this is not always the case.
If you’re using a phone or MP3 player connected to a USB connection, it’s often enough to simply select the auxiliary or USB input. Some head units, in combination with certain phones, will also include additional features and may require you to open the corresponding app on the head unit.
Listening to music stored on a USB drive is often more difficult. You may be lucky and everything will work fine the first time you connect the joystick, or it may take a little longer. For example, you may find that your head unit can only read data from your thumb if it is formatted in a certain way, such as FAT32 or NTFS . You may also have to dive into the head unit options to specify where to find music on the thumbnail, or there may be a «sync» option that will prompt the head unit to automatically find music on any media connected.
Using Other USB Car Audio Features
USB is an interesting type of connection because it is capable of transferring both data and power at the same time. However, not all USB ports are connected in the same way. In addition to USB ports that can perform both functions, some are data-only and others are power-only.
When a car stereo comes with a built-in USB port, it is typically plugged in to provide power in addition to the data connection. While the data connection is the primary purpose of the port, this type of car audio USB connections can also be used to charge your phone or turning on other USB devices.
As USB is increasingly used in place of proprietary power ports in all kinds of portable electronics, the USB power port on the head unit can be used to charge or power anything from a phone, to a portable GPS navigation device, and everything in between.
If your head unit does not have a powered USB connector, you will only be able to use it to play music. There are also several situations, especially with Apple devices, where the device does not charge properly. This is primarily due to different devices recognizing that a USB port is a charging port instead of a simple data port.