With various charging standards and technologies in place, it’s much harder than it should be to figure out what a cable can do. There are a few things worth knowing when purchasing.
USB standards: The Universal Serial Bus (USB) standard dates back to 1996, but has seen many new standards, revisions, and connector types in the years since. Instead of going over them all here, we tried to highlight what matters.
Connectors: While USB-C is thankfully becoming a standard connection type, you want cables with connectors that fit your existing devices. Today, that could still mean USB-A, Lightning, or even MicroUSB. Remember that the capabilities of any cable are limited to its oldest connection type.
Data: The data transfer speed is always in megabits per second (Mbps) or gigabits per second (Gbps). You will know the speed that a cable must reach according to the standard:
- USB 2.0 supports 480 Mbps
- USB 3.0 supports 5Gbps
- USB 3.1 supports 10Gbps
- USB 3.2 Gen 1 supports 5Gbps
- USB 3.2 Gen 2 supports 10Gbps
- USB 3.2 Gen. 3 supports 20 Gbps
- USB 4.0 supports 40 Gbps
Force: While cable manufacturers always list the maximum charging speed, your device will determine how much power it consumes, so it’s important to know what standards it supports and pair your cable with the correct power adapter. The charging speed of a cable is measured in watts (W). Sometimes manufacturers list cable specifications in fine print. If W is not listed, you can calculate it by multiplying the voltage (V) and current (A), assuming they are listed.
Basic USB-C cables are passive and can only carry up to 60W. Cables that can carry 100W or more, sometimes described as active, must contain electronic marker chips that identify the cable and its capabilities.
The Power Delivery (PD) standard is the closest thing we have to a common standard. Some manufacturers, such as OnePlus, Oppo and Xiaomi, still have proprietary charging standards. Then there’s Qualcomm’s Quick Charge (QC) standard, which was the most popular for phones for many years, although Quick Charge 4+ supports PD. Even PD has a variant called Programmable Power Supply (PPS), which is part of the USB PD 3.0 standard. PPS allows real-time adjustments to be made to maximize efficiency and charge phones like Samsung’s Galaxy S22 range at up to 45W instead of the usual 18W. The latest addition to PD is Extended Power Range (EPR), which allows USB-C cables to carry up to 240 watts (they used to be limited to 100W).
Thunderbolt was a proprietary interface developed by Intel and Apple, but is now open for royalty-free use (still certified by Intel). With Thunderbolt 3, the standard adopted the USB-C connector and is capable of data transfer speeds of up to 40 Gbps and can deliver 100 watts of power using the PD standard. Thunderbolt 4 brings several improvements mainly related to the video signal (support for two 4K displays or one 8K display). It also supports the USB 4 standard and is backward compatible.
Cable certification: There are some types of cable certification. When a cable is certified, it usually means that it was independently tested and meets specific standards. It gives you, as a buyer, peace of mind knowing that your cable performs as the manufacturer claims. Certification can be expensive, so many cable manufacturers avoid it, but that doesn’t necessarily mean their cables are poor quality. He USB Implementers Forum (USB-IF) is a non-profit organization dedicated to the advancement of USB technology. Led by members such as Apple, Google, HP, Microsoft and Intel, it sets specifications and offers certification. If a cable is USB-IF certified, it has been tested to ensure it meets their standards. Apple has its own Made for iPhone (MFi) certification for Lightning cables. Intel certifies Thunderbolt cables. Certified cables usually have a corresponding logo on the connector (for example, Thunderbolt cables have a lightning bolt).