USB-C explained: How to get the most from it (and why it keeps getting better)
At the office, home or school, USB-C has arrived. We’ve got tips on how to take advantage of those new ports, along with
a peek at the future of data transfer and video.
You’ve probably noticed something strange about many of the latest phones, tablets and laptops at your company: The
familiar rectangular Type-A USB ports are gone, replaced by smaller oblong connectors. USB-C has taken over at work, at home
and at school.
While many iPhone and iPad models stick with Apple’s proprietary Lightning connector, USB-C is now part and parcel of
most laptops, phones and tablets made today. Even the latest MacBooks and Chromebooks are part of the movement to USB-C.
What is USB-C?
USB Type-C, usually referred to as just USB-C, is a relatively new connector for delivering data and power to and from
computing devices. Because the USB-C plug is symmetrical, it can be inserted either way, eliminating the frustrations of
earlier USB ports and putting it on a par with Apple’s reversible Lightning plug.
This alone makes it a hit for me, but USB-C is closely linked to several powerful new technologies, including Thunderbolt
and USB Power Delivery, that can change how we think about our gear and working in the office, on the road or at home.
Most USB-C ports are built on the second-generation USB 3.1 data-transfer standard, which can theoretically deliver data
at speeds of up to 10Gbps — twice as fast as USB 3.0 and first-gen USB 3.1, which both top out at 5Gbps. The key is to get
devices that say “USB 3.1 Rev 2,” “USB 3.1 Gen 2,” “SuperSpeed USB 10Gbps,” or “SuperSpeed+” to get support for the
faster spec.
Confusing matters more, the current USB 3.2 standard is mostly a restatement of USB 3.1 specs. For instance, USB 3.2 Gen
1 and 2 are the same as USB 3.1 Gen 1 and 2. The new spec that’s actually noteworthy is USB 3.2 Gen 2X2, which has a pair of
10Gbps lanes of data traffic available for a total of 20Gbps. So far, however, it hasn’t caught on with device
manufacturers, so it’s hard to find it on any devices in the wild. That might change in the coming year as new controller
chips come out.
To make sure the data gets through at higher speeds, always get
high-quality cables. They
will often have the SuperSpeed logo and a “10” on them to show they’re capable of moving 10Gbps. The good news is that
there’s a good chance that this spaghetti bowl of cable standards could disappear with the next rev of the USB spec with a
universal USB cable. More on that later.
Speed, power, and video delivery
A big bonus is that on many laptops and desktops, the USB-C specification also supports Intel’s Thunderbolt 3 data-
transfer technology. A USB-C port equipped with Thunderbolt 3 can push data speeds to a theoretical limit of 40Gbps. To show
how far we’ve come, that’s four times faster than USB 3.1 and more than 3,000 times faster than the original USB 1 spec of
12Mbps.
With increased data-transfer speeds comes the ability to push video over the same connection. USB-C’s Alternate Mode (or
“Alt Mode” for short) for video enables adapters to output video from that same USB-C port to HDMI, DisplayPort, VGA and
other types of video connectors on displays, TVs and projectors. It pays huge dividends for the ultramobile among us by
allowing many recent phones and tablets, such as the Samsung Galaxy Tab S7+ and Note and Tab 6 systems, to directly plug into
a monitor at home or a projector in the office.
What’s more, USB-C supports the USB Power Delivery (USB PD) specification. A USB 2.0 port can deliver just 2.5 watts of
power, about enough to charge a phone, slowly. USB 3.1 ups this figure to about 15 watts. But USB PD can deliver up to 100
watts of power, more than six times what USB 3.1 can. This opens up the potential for laptop-powered projectors based on
USB-C, but today it is mostly used for
high-power chargers and external
battery packs.
Next up: USB4
With USB-C accepted as the de facto connector today, the next step is USB4. It can move up to 40Gbps, provide at least 15
watts of power for accessories, and support two 4K displays or a single 8K display. To its credit, USB4 will continue with
the small oblong connector that USB-C brought to the party and will work with existing devices, including USB 2.0 ones. (You
will need the right adapter for devices without a USB-C port, though.)
Behind the scenes, USB4 uses the Thunderbolt 4 spec. It sets up bidirectional lanes of data that should help things like
videoconferencing, which require two-way data flow to prevent congestion and jams. In addition to extra security to prevent a
hack attack, Thunderbolt 4 will be compatible with Thunderbolt 3 devices, like docking stations and External Graphics
Processing Units (eGPUs). It includes dynamic data flow that is adjusted to suit the devices, so older devices won’t slow
down newer ones.
On the downside, you’ll need a Thunderbolt 4 cable to make it work, but there’s a potential bonus: all Thunderbolt 4
cables will be able to be used on anything from USB 2 (with adapter) through USB4 systems. This will make it as close to a
universal data cable as exists today. They’ll be available in 2-meter lengths (about 6? feet), more than twice the standard
0.8-meter length of current USB-C cables. The key to look for when shopping is that they will have the iconic Thunderbolt
lightning icon and a 4 on the plug.
The USB4/Thunderbolt 4 spec is built into Intel’s 11th-generation Tiger Lake processors, although the company and others
will have standalone USB4 controller chips. The first computers with Thunderbolt 4 ports might appear in late 2020 and
devices that plug into them early the next year.
Making USB-C work for you
In the here and now, you’ll need to make some changes and buy some accessories to take full advantage of USB-C. This
guide can help ease the transition by showing what you can do with USB-C and what you’ll need to make it work.
Be careful, because not all USB-C devices support all of the latest USB-C specs. For instance, just about every USB-C
flash drive supports the earlier USB 3.1 Rev 1 protocol, some tablets and phones don’t support Alt Mode video, and we are in
the early days of USB Power Delivery, with few devices going beyond 40 or 60 watts. In other words, read the spec sheet
carefully so you know what you’re getting before you buy.
These tools, tips and DIY projects can help make the transition to a USB-C world easier.
Make a USB-C travel kit
The good news is that USB-C ports can be used with most older USB 2, 3.0 and 3.1 accessories. The bad news is that
you’ll need the right
adapters and cables, and so far, I haven’t seen
a complete kit available. I’ve made my own USB-C survival kit that has six key cables and adapters inside an old zippered
case.
Find the right power adapter and cable for your Mac notebook
Learn which power adapter, cable, and plug works with your Mac notebook computer.
Power adapters for Mac notebooks are available in 29W, 30W, 45W, 60W, 61W, 85W, 87W, and 96W varieties. You should use
the appropriate wattage power adapter for your Mac notebook. You can use a compatible higher wattage power adapter without
issue, but it won't make your computer charge faster or operate differently. If you use a power adapter that is lower in
wattage than the adapter that came with your Mac, it won't provide enough power to your computer.
Mac notebooks that charge via USB-C come with an Apple USB-C Power Adapter with detachable AC plug (or duckhead), and a
USB-C Charge Cable.
Mac notebooks that charge via MagSafe come with an AC adapter with MagSafe connector and detachable AC plug, and an AC
cable.
Make sure you're using the correct USB-C charge cable and
bluetooth
glasses
For the best charging experience, you should use the USB-C charge cable that comes with your Mac notebook. If you use a
higher wattage USB-C cable, your Mac will still charge normally. USB-C cables rated for 29W or 30W will work with any USB-C
power adapter, but won't provide enough power when connected to a power adapter that is more than 61W, such as the 96W
USB-C Power Adapter.
You can verify that you're using the correct version of the Apple USB-C Charge Cable with your Mac notebook and its
USB-C AC Adapter. The cable's serial number is printed on its external housing, next to the words Designed by Apple in
California. Assembled in China.
If the first three characters of the serial number are C4M or FL4, the cable is for use with an Apple USB-C Power Adapter
up to 61W.
If the first three characters of the serial number are DLC, CTC, FTL, or G0J, the cable is for use with an Apple USB-C
Power Adapter up to 100W.
If the cable says Designed by Apple in California. Assembled in China but has no serial number, you might be eligible for
a replacement USB-C charge cable.