USB C cables can have variations in speed, power, and protocol capabilities. Additionally there are different length requirements to watch out for. When in doubt, buy cables from the device manufacturer. You can also buy USB C cables from Adafruit as we have specific cables for specific needs that are all tested and researched.

Speed

A USB C cable with 3.1 Gen 2 capabilities vs one with 2.0 can mean a vast difference in data transfer. For example, two cable types transferring the same HD movie can take vastly different times:

• 3.1 Gen 2 takes 5 seconds at 10 Gbps
• 2.0 takes 1.7 min at 480 MBps

USB C cables run at different speeds measured in bits per second. These include:

• USB 2.0
• 480 Mbps (megabits per second)
• USB 3.0
• 5 Gbps (gigabits per second)
• USB 3.1 Gen 1
• 5 Gbps
• USB 3.1 Gen 2
• 10 Gbps
• *Note USB 3.1 gen 4 in store?”
• USB 3.2 and 4.0
• These cables will not be covered in this guide at this time, as they are not yet widely adopted.

If you run across the term “Full-featured” this a reference to speed and typically means USB 3.1 Gen 2.

Power

All USB-C cables must be able to carry a minimum of 20V 3A, but can also carry high-power 20V 5A current.

For cables with up to 3A and 5A delivery, they can be used for

• Charging USB type C enabled devices such as cell phones and tablets. 
• Transferring photos and music between devices.

The biggest difference between 3A and 5A cables is 5A cables can generally power laptops and monitors while 3A cables cannot. 

Protocols / Alternate Modes:

Different USB C cables may support different protocols, or ways of transferring data, such as MHL, HDMI, Thunderbolt 3 and DisplayPort. In relation to USB C, these protocols are called alternate modes. Having support for one protocol type may give support for another but this is not generally the case. 

MHL (Mobile High-Definition) 

• Connects smart phones to TVs.
• Allows MHL-enabled source and display devices to be connected through a USB Type C port.
• Look for MHL support on product page where you are ordering from to ensure MHL is supported.

HDMI

• Allows HDMI-enabled sources with a USB C connector to directly connect to standard HDMI display devices without requiring an adapter.
• Look for HDMI support..

Thunderbolt 3

• Typically used for monitors and 4K support. This gives a large speed boost when transferring data at 40 Gbps.
• Can require active cables for higher performance, if over 0.5 meters. 
• Thunderbolt 3 cables also support the DisplayPort protocol.

DisplayPort

• Another type of digital display interface, backwards compatible with HDMI/DVI/VGA.
• Look for DisplayPort support.

Length

In general, the faster the speed of a USB cable, the shorter it should be due to the electrical characteristics inherent to high speed data transfer.

Here are the different cable speeds and corresponding suggested lengths:

USB 2.0

• Up to 4 meters.

USB 3.1 Gen 1

• Up to 2 meters.

USB 3.1 Gen 2

• Up to 1 meter.

Thunderbolt 3 cables

• If the cable is over half a meter, it needs to be a special active cable, meaning there are a bit of electronics inside to help things out.
• If 0.5 m or under, can be passive. The only thing under the rubber sheathing is copper wire.
• For more details, check the product pages of the cables you are considering.