With so many different standards and charging technologies in play, figuring out what a cable can do is harder than it sounds. There are a few things you should know when shopping.
USB standard: The Universal Serial Bus (USB) standard was established in 1996, and since then many new standards, revisions, and connector types have emerged. I won’t explain them all here, but will focus on the important ones.
connector: USB-C is thankfully becoming a standard connection type, but you’ll need a cable with a connector that fits your existing device. Today, that could still mean USB-A, Lightning, or even MicroUSB. Please note that the functionality of any cable is limited to its oldest connection type.
data: Data transfer rates are always expressed in megabits per second (Mbps) or gigabits per second (Gbps). Standards tell you what speeds a cable can support.
- USB 2.0 supports 480Mbps
- USB 3.0 supports 5Gbps
- USB 3.1 supports 10Gbps
- USB 3.2 Gen 1 supports 5 Gbps
- USB 3.2 Gen 2 supports 10 Gbps
- USB 3.2 Gen 3 supports 20 Gbps
- USB 4.0 supports 40Gbps
force: Cable manufacturers always list a maximum charging speed, but how much power it draws is determined by the device, so it’s important to understand the standards your device supports and pair your cable with the correct power adapter . Cable charging speed is measured in Watts (W). In some cases, the manufacturer will include specifications for the cable in small print. If W is not listed, it can be calculated by multiplying the voltage (V) by the current (A), assuming it is.
Basic USB-C cables are passive and can only transmit up to 60 watts. Cables capable of transmitting 100 watts or more (sometimes referred to as active) must contain an e-marker chip that identifies the cable and its function.
The Power Delivery (PD) standard is as close as you can get to a common standard. Some manufacturers, such as OnePlus, Oppo, and Xiaomi, still have their own charging standards. Then there’s Qualcomm’s Quick Charge (QC) standard. Quick Charge 4+ supports PD, which has been the most popular in mobile phones for many years. PD also has a variant called Programmable Power Supply (PPS), which is part of the USB PD 3.0 standard. PPS allows for real-time adjustments to maximize efficiency, allowing phones such as Samsung’s Galaxy S22 series to charge at up to 45 watts instead of the usual 18 watts. The latest addition to PD is Extended Power Range (EPR), which allows transmission over a USB-C cable. Up to 240 watts (previously limited to 100 watts).
Thunderbolt was a proprietary interface developed by Intel and Apple, but is now available royalty-free (though still certified by Intel). Thunderbolt 3 adopts the USB-C connector as a standard, allowing data transfer speeds of up to 40 Gbps, and can deliver 100 watts of power using the PD standard. Thunderbolt 4 brings various improvements, primarily related to video signals (support for two 4K displays or one 8K display). It also supports the USB 4 standard and is backward compatible with previous standards.
Cable certification: There are several types of cable certifications. When a cable is certified, it usually means that it has been independently tested and complies with certain standards. This gives buyers peace of mind that the cable will perform as claimed by the manufacturer. Certification is expensive, so many cable manufacturers avoid it, but that doesn’t mean their cables are of poor quality. of USB Implementer Forum (USB-IF) is a nonprofit organization dedicated to the advancement of USB technology. Operated by members including Apple, Google, HP, Microsoft, and Intel, it sets specifications and provides certifications. If a cable is certified by USB-IF, it has been tested for compliance with that standard. Apple has its own Made for iPhone (MFi) certification for its Lightning cable. Intel certifies Thunderbolt cables. Certified cables typically have an associated logo on the connector. (For example, Thunderbolt cables have lightning bolts on them.)
