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The impossible dream of USB-C

I love the idea of USB-C: one port and one cable that can replace all other ports and cables. It sounds so simple, straightforward, and unified.

In practice, it’s not even close.

USB-C normally transfers data by the USB protocol, but it also supports Thunderbolt… sometimes. The 12-inch MacBook has a USB-C port, but it doesn’t support Thunderbolt at all. All other modern MacBook models support Thunderbolt over their USB-C ports… but if you have a 13-inch model, and it has a Touch Bar, then the right-side ports don’t have full Thunderbolt bandwidth.

If you bought a USB-C cable, it might support Thunderbolt, or it might not. There’s no way to tell by looking at it. There’s usually no way to tell whether a given USB-C device requires Thunderbolt, either — you just need to plug it in and see if it works.

Much of USB-C’s awesome capability comes from Thunderbolt and other Alternate Modes. But due to their potential bandwidth demands, computers can’t have very many USB-C ports, making it especially wasteful to lose one to a laptop’s own power cable. The severe port shortage, along with the need to connect to non-USB-C devices, inevitably leads many people to need annoying, inelegant, and expensive dongles and hubs.

While a wide variety of USB-C dongles are available, most use the same handful of unreliable, mediocre chips inside. Some USB-A dongles make Wi-Fi drop on MacBook Pros. Some USB-A devices don’t work properly when adapted to USB-C, or only work in certain ports. Some devices only work when plugged directly into a laptop’s precious few USB-C ports, rather than any hubs or dongles. And reliable HDMI output seems nearly impossible in practice.

Very few hubs exist to add more USB-C ports, so if you have more than a few peripherals, you can’t just replace all of their cables with USB-C versions. You’ll need a hub that provides multiple USB-A ports instead, and you’ll need to keep your USB-A cables for when you’re plugged into the hub — but also keep USB-C cables or dongles around for everything you might ever need to plug directly into the computer’s ports.

Hubs with additional USB-C ports might pass Thunderbolt through to them, but usually don’t. Sometimes, they add a USB-C port that can only be used for power passthrough. Many hubs with power passthrough have lower wattage limits than a 13-inch or 15-inch laptop needs.

Fortunately, USB-C is a great charging standard. Well, it’s more of a collection of standards. USB-C devices can charge via the slow old USB rates, but for higher-powered devices or faster charging, that’s not enough current.

Many Android phones support Qualcomm’s Quick Charge over USB-C, which is different — usually — from the official, better, newer USB-C Power Delivery (PD) standard. Apple products, some Android phones, and the Nintendo Switch use USB-C PD. Quick Charge devices don’t get any benefit — usually — from PD chargers, and vice versa.

Your charger, cable, and any standalone batteries you want to use all must support the same charging standard for it to work at full speed.

Some cables don’t support USB-C PD at all, and most don’t support laptop wattages. Apple’s cable supports USB-C PD charging at high wattages… unless you bought the earlier version that doesn’t. Most standalone batteries sold to date don’t support USB-C PD — there are only a handful on the market so far, and most of them can’t charge a laptop at full speed, unless it’s the 12-inch MacBook.

You can use USB-C PD to fast-charge an iPhone 8 or iPad Pro with a USB-C to Lightning cable. But it doesn’t work with every USB-PD battery or charger, or every USB-C to Lightning cable, or every iPad Pro.

And, of course, there’s usually no way to tell at a glance whether a given cable, charger, battery, or device supports USB-C PD or at what wattages.

It’s comforting to think that over time, this will all settle down and we’ll finally achieve the dream of a single cable and port for everything. But that’s not how technology really works.

Before today’s USB-C can become ubiquitous and homogeneous, the next protocol or port will come out. We’ll have new, faster USB 4.0 and Thunderbolt 4 standards over the same-looking USB-C ports. We’ll want to move to an even thinner USB-D port. The press will call it “the future” and Apple will celebrate its new laptops that only have a USB-D port — two, if we’re lucky.

And we’ll have to start over again, buying all new cables, dongles, hubs, chargers, batteries, and displays to adapt it to what we really need.

Maybe next time, we’ll get it right. But probably not.