USB-C explained: How to get the most from it (and why it keeps on getting better)

Now that you’re used to seeing co-workers, family, and strangers at coffee shops, offices, and planes using the oblong USB-C connector, it’s time to see just what this promising standard can do today and tomorrow. As we approach its 10th birthday, the USB-C plug is now part and parcel of just about every new laptop, phone, and tablet made. Even MacBooks, iPads, iPhones, and Chromebooks now have USB-C ports, at least living up to the first part of its full name: Universal Serial Bus.

In other words, the older rectangular USB Type-A plugs we are so used to are slowly going the way of the dinosaur. This evolution is happening faster in some arenas than others. For example, the latest Mac Pro desktop has no fewer than eight USB-C ports for anything from sending video to a display to charging a phone.

Melissa Riofrio/IDG

What is USB-C?

Without a doubt, USB Type-C, commonly referred to as USB-C, is becoming the standard connector for moving data and power to and from a wide variety of computing devices. Its symmetrical design means it can be inserted either way — up or down — eliminating many of the frustrations of earlier USB ports.

This alone makes it a hit for me. No more fumbling with plugs that always seem to be upside down.

Because it is a connector specification and not a data transfer protocol, USB-C has been a constant as the underlying technology for moving data and powering devices has evolved. It’s closely linked to several powerful new technologies, including Thunderbolt and Power Delivery, that have the potential to change how we think about our gear and how we work in the office, on the road, and at home.

It’s when we start talking about protocols that things get messy. The five main USB protocols in use today are confusing, to say the least, creating an alphabet soup of standards that could muddle the most technical among us.

Here is a breakdown of the USB specifications, where it’s best to concentrate on the data flow levels:

• Today, the most popular USB spec is the USB 3.2 Gen 1 protocol that allows a maximum throughput of 5Gbps to travel over a single lane of data and can use an old-school Type-A rectangular plug or the oblong USB-C connector.
• The next step up has two alternatives: the use of double speed lanes of data that abide by the 5Gbps speed limit (USB 3.2 Gen 1×2) as well as a single-lane variant that operates at twice the speed (USB 3.2 Gen 2×1). Generally compatible with each other, the result is 10Gbps peak throughput.
• The USB 3.2 Gen 2×2protocol uses two lanes of double-speed data traffic to top out at 20Gbps.
• USB4 (no space between “USB” and “4”) is the newest protocol and incorporates the Thunderbolt 4 spec. Within USB4, there are several variants that provide 5, 10, 20 and 40Gbps of peak flow.

What’s in a name? USB specs and speeds

The final contemplated step up is USB4 v2, which takes data transfer speeds to new heights by using PAM-3 pulse amplitude modulation technology. Derived from 10Gbps Ethernet wired networking, PAM-3 tops out at 80Gbps in symmetric mode and gets to the spec’s top speed of 120Gbps in asymmetric mode. Unfortunately, these speed upgrades are off in the future.

Next up: Thunderbolt 5

Using USB4 v2 as a starting point, the next stage of USB-C’s development will incorporate Thunderbolt 5, which was debuted by Intel last fall. Under normal circumstances, it can move a maximum of 80Gbps, double the rate of Thunderbolt 4 and USB4. This will help with everything from moving data onto and off flash drives to running backups of company data and multipurpose docking stations.

But if more throughput is needed — such as for 8K video, which can require 50Gbps — it uses a clever technique known as Bandwidth Boost. This pushes its speed limit to 120Gbps when needed. It can also be useful for feeding video to a screen at a refresh rate of up to 544Hz, which might find a home with a company’s CAD designers, traders, or video editors.

It’s another case of hurry up and wait. With Thunderbolt 4 gear just coming to market, expect to see computers with TB5 in 2024 and the first round of accessories in 2025. At the moment, there is no corresponding USB5 spec.

Gear up for new USB-C capabilities

Despite the confusing name-game, older devices continue to work with the newer specs. In other words, that two-year-old USB-C flash storage key will work with your newest laptop, although not always at top speed.

To take full advantage of USB-C today, though, you’ll need to get some new gear. Be careful, because not all USB-C devices on the market support all the latest USB specs. For instance, just about every USB-C flash drive sold today supports the earlier USB 3.2 Gen 1 protocol, and some tablets and phones don’t support Alt Mode video (more on that in a moment). It’s best to read the spec sheet carefully so you know what you’re getting before you buy.

I tried out some newer USB-C accessories to see the latest capabilities for myself. Here’s what to expect.

Docking station

In the here and now, the first USB4 devices flooding the market are docking stations that can make a laptop feel right at home on a desktop, moving data while charging the system. The $290 Plugable TBT4-UDX1 dock is connection central, with 11 ports and the ability to stream up to 96 watts to charge a laptop. It includes four USB Gen 2 Type A ports capable of 10Gbps, two USB-C connections that can push 40Gbps, and a 2.5Gbps networking port. There are also more mundane amenities like an SD card slot, a headphone jack, and HDMI for video.

Plugable

By using a combination of the USB-C and HDMI ports, the UDX1 can drive up to two 4K monitors or a single 8K screen — that is, if you have the right cables and adapters.

Getting it set up on my desk was a snap, because it didn’t require any extra software. I plugged in the dock’s power adapter, connected it with the included Thunderbolt 4 cable to my Acer Swift Edge 16 notebook, and it immediately started charging my system as fast as its included AC adapter. The dock worked smoothly with my keyboard, mouse, and wired Ethernet connection, as well as an Epson PowerLite L260F projector and my Logitech game controller, because 9 to 5 only lasts until 5PM.

Fast data storage

The UDX1 came into its own with the Kingston XS2000 USB 3.2 2X2 flash drive plugged in and connected to the Acer Swift Edge 16 laptop. Somewhat larger and heavier than the typical flash drive, the XS2000 measures 2.7 x 1.3 x 0.5 inches and weighs 1 ounce. It fits into a pocket but requires a USB-C cable to connect.

Kingston

The XS2000 read data at 7.90Gbps, as measured by the CrystalDiskMark benchmark software — that’s less than half the spec’s 20Gbps speed limit but a huge increase from the 1.23Gbps that I got using a SanDisk USB 3.1 flash drive. Kingston sells XS2000 drives for $86 (500GB), $140 (1TB), $246 (2TB) and $450 (4TB).

Unfortunately, USB4 is so new that there weren’t any external drives available for my tests. So, I made one myself. Using the $120 Satechi USB4 NVMe SSD Pro drive enclosure, I plugged in a Crucial P3 Plus 500GB SSD module. It upped the data reading rate to an exceptional 29.5Gbps, about three-quarters of the 40Gbps spec and one of the fastest drives available anywhere. Stay tuned: I’ll show you how to make the drive later in the story.

Power Delivery

While a USB 2.0 port could deliver just 2.5 watts of power, about enough to slowly charge a phone, USB 3.1 upped this to about 4.5 watts, and the initial uses of USB-C topped out at 15 watts of power. Today, a single USB-C cable can handle both video and power using USB’s Power Delivery spec.

Happily, USB4 increases this output to 100 watts for the base protocol and as much as 240 watts with the Extended Power Range specification. For practical reasons, most devices limit this to between 96 and 100 watts.

Still, this opens up a brave new world of laptop-powered projectors based on USB-C. Unfortunately, though, I couldn’t find any such products to test; Power Delivery is today being used mostly for chargers, external battery packs, and displays.

Alt Mode displays

The newest USB-C cables are capable of delivering video using USB-C’s Alternate Mode, or “Alt Mode.” At the moment, a Thunderbolt 4/USB4 cable can push 8K video or supply several 4K displays. This breakthrough can neaten a desk by getting rid of at least one cable.

For instance, Samsung’s 43-inch M70B display can use a USB-C cable to not only send video from a laptop to the screen but also send power the other way to charge the system. The $430 model I looked at has a resolution of 3840 x 2160 pixels and was able to charge my Acer Swift Edge 16 and my Google Pixel 7 phone.

Brian Nadel / IDG

Cables

To get the most out of the new specs and the gear, you’ll need the right cables. Happily, after a proliferation of cable types, there’s a convergence going on. All Thunderbolt 4 cables will get the most out of USB4 devices, as well as all the specs that came before it. In fact, it’s so much of a no-brainer that all I buy these days are TB4 cables. They work well for anything from moving data off my phone to feeding video to a display or backing up data to a drive.

The reason they work with all specs is that each USB cable has an identification chip inside that senses the hardware’s capability and sets the speed and power abilities accordingly. Called e-marker, the integrated circuit is at both ends of the cable so that the USB device can query the cable’s capabilities and adjust the top speed to suit it. Older USB-C cables will generally work, just not always at top speed and might not work with the newest equipment.

Apple

Most of these cables are available in up to 2-meter lengths (about 6.6 feet), which is more than twice the standard 0.8-meter (31-inch) length of earlier USB-C cables. That said, there are also one-meter cables from Satechi and Plugable for $30 and $29. By contrast, Apple pushes Thunderbolt 4 cabling to 3 meters (9.8 feet), but its Thunderbolt 4 Pro cable is pricey at $159.

One of my favorite USB-C cables is the Baseus Free2Draw Mini Retractable USB-C Cable 100W. Inside the Free2Draw’s small circular cable winder is a 3.3-foot USB 2.0 cable that can be spooled out at 1.1-, 1.9-, 2.7- or 3.3-foot lengths without getting tangled. Capable of delivering 100 watts to charge a phone, tablet, or laptop, it tops out at only 480Mbps of data.

Next page: USB-C tools, tips, projects, and troubleshooting advice →