Which USB device is it

Information about USB on Mac computers

Learn about the types and functions of USB ports on your Mac.

Types and names of USB ports

USB (Universal Serial Bus) is an industry standard for connections between computers and other devices. It is available for many connection types, and each type has its own shape. Depending on the Mac model, USB is available on the Mac in the form of the following ports:


USB-A type connectors are commonly referred to as USB, USB 2, or USB 3 ports. Which of these terms applies in detail depends on which USB specification you support. The USB-A connector will only fit into the port in the correct orientation.


USB-C ports are available as standard USB-C ports on the Mac, Thunderbolt 3 ports and Thunderbolt / USB 4 ports to disposal. These all look the same, and the connector can be inserted in either direction.

USB specifications

USB specifications are especially important if you want to get the most out of your USB device in terms of speed and performance, or if your device needs more power or uses too much power. Each USB port supports a specific USB specification. It determines the maximum data transfer rate (speed) of the connection as well as the amount of power provided, provided that both the device and the USB cable meet at least the specification.

USB specifications on MacData transferPower supply
USB 4Up to 10 Gbit / sUp to 15 W at 5 V.
USB 3.1 Gen 2
Also known as USB 3.2 Gen 2
Up to 10 Gbit / sUp to 15 W at 5 V.
USB 3.1 Gen 1
Also known as USB 3.2 Gen 1 or USB 3
Up to 5 Gbit / sUp to 900 mA at 5 V.
USB 2.0
Up to 480 Mbit / sUp to 500 mA at 5 V.
USB 1.1
Up to 12 Mbit / sUp to 500 mA at 5 V.

To find out which specification is supported by a USB-A or USB-C port on your model of Mac, do the following:

  • Choose Apple menu ()> About This Mac, click Support, then click Specifications.
  • The System Information app provides more details, including about USB devices connected to USB ports on your Mac. Select USB in the sidebar, then select a USB port on the right.

Get the best performance from your USB devices

All USB specifications are compatible with each other. However, the cable or device using the oldest specification will limit its speed and performance. For example, if you connect a USB 3 device to a USB 2 port, your device is limited to the speed of USB 2 and cannot draw more power than USB 2 can provide. In other words, for the best performance, make sure that the USB port on your Mac and the USB cable to your device match at least the USB specification of the device itself.

If your Mac doesn't recognize the USB device after connecting it to the Mac:

  • Check all connections: disconnect the device from your Mac, then reconnect it. Make sure that all cables and adapters are securely connected at both ends. Try a different cable or adapter, if available.
  • Connect the device directly to your Mac instead of a USB hub or other device. If necessary, test the connection with a different USB port on the Mac or device.
  • Some devices require their own software such as drivers or firmware. Others work without additional software. Check with your device manufacturer and also install any available Apple software updates.
  • If you received your device with a power adapter, use this. Some devices can be powered from the USB port on your Mac. Others use more power than your Mac can provide.
  • Restart the Mac.

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