A complete nightmare: USB-C and Thunderbolt 3

Original author: Stephen Foskett
  • Transfer
Have you bought yourself a new MacBook or MacBook Pro? Or maybe Google Pixel? You are on the verge of confusion thanks to these new “USB-C” ports. This plain-looking port harbors universal confusion, and blessed backward compatibility uses different cables for different tasks. Buyers will have to very carefully choose their cable!



USB Type-C: ports and protocols


The USB Type-C ports have spread quite widely, Google started using them on their computers and Pixel and Nexus phones, Apple uses them on the 12 "MacBook, and now on the new MacBook Pro. This is the physical specification for the 24-pin two-way plug and the corresponding cables. In this article, I will refer to this physical cable and port as “USB-C” as the most commonly used term. Google reports that this port is called “USB-C” 21 million times, “USB C” 12 million times, and correct, “USB Type-C”, only 8.5 million times.


USB-C compatibility: multiple protocols are supported, and each level is backward compatible with levels below

USB-C allows different signals to pass through:

• USB 2.0 - oddly enough, the earliest USB-C devices, including the Nokia N1, supported signals and USB 2.0 powered only. Almost all new computers support at least USB 3.0, but some phones and tablets still have limitations.

• USB 3.1 gen 1 - very similar to “SuperSpeed” USB 3.0, 5 Gb / s serial communication for all peripherals, from hard drives to network adapters and docking stations. Backward compatible with SuperSpeed ​​USB 3.0, Hi-Speed ​​USB 2.0 and even the original USB 1.x from 1996! This protocol is used by Apple in a 12 ″ MacBook.

• USB 3.1 gen 2 - confusing name doubles the bandwidth of USB peripherals up to 10 Gbps. Backward compatible with all previous USB versions. It is supported only by the latest USB-C devices. I wonder who just came up with this name.

• Alternate Mode (alternate mode) —The USB-C physical connector supports other non-USB protocols, including DisplayPort, MHL, HDMI, and Thunderbolt. But not every device supports the Alternate Mode protocol, which is very confusing for buyers.

• Power Delivery is not a data protocol, but USB-C allows up to 100 watts of power. But again, there are two different specifications and many different configurations.

• Audio Accessory Mode (audio accessory) - specification for use with analog audio.

The main problem of USB-C is confusion. Not every USB-C cable, port, device, and power will be compatible with each other, and many combinations will have to be considered. The newest, most sophisticated devices (for example, a MacBook Pro with Touch Bar) will support most of the various port uses, but common old devices only support USB 3.0 and, if lucky, Alternate Mode DisplayPort.

But that's not all. Many USB-C peripherals also have limitations. Imagine a USB-C HDMI adapter. It can realize HDMI via USB 3.0, and it can use native HDMI Alternate Mode. It can also use HDMI multiplex with Thunderbolt Alternate Mode, and even, theoretically, HDMI via Thunderbolt using an external graphics chip! It was I who advertised the idea of ​​Thunderbolt Display with an integrated GPU. And only the newest computers will support all three modes. Imagine how confused the consumer, who bought the adapter "USB-C HDMI", having discovered that it does not work with MacBook or Pixel or something else?

Cable nightmare



StarTech Thunderbolt 3 USB-C Cable (40 Gbps)


Monoprice Palette Series 3.1 USB-C to USB-C with PD (10 Gbps, 100 Watts)


Monoprice Palette Series 3.0 USB-C to USB-C (5 Gbps, 15 Watts)


Monoprice Palette Series 2.0 USB-C to USB-C (480 Mbps, 2.4 Amps)

These cables look the same, but the possibilities are very different! (In my opinion, Monoprice placed one photo for two different cables)

Problems with cable compatibility are even more serious. Many companies, including my beloved Monoprice, make USB-C cables of different quality and compatibility. If you are not careful, you can limit the possibilities or even damage your devices with the wrong cable. Seriously: the wrong cable can damage your device! This should not be, however, here it is.

Some USB-C cables at both ends can transfer only 5 Gbps, others are compatible with 10 Gbps USB 3.1 gen 2. Others cannot be used for power, or they are not compatible with Alternate Mode Thunderbolt. Look at Monoprice 3.1 10 Gbps / 100-Watt USB-C to USB-C, 3.0 5 Gbps / 15 Watt USB-C to USB-C and 2.0 480 Mbps / 2.4 A USB-C to USB-C. Why do they exist at all? Why do you need a USB-C to USB-C cable with support for only 2.0?

And there are also cables with different connectors at the ends. Monoprice sells a cool USB-C adapter to USB 3.0 10 Gbps, but it also has one that supports 5 Gbps, and even a limited 480 Mbps USB 2.0. And they look almost the same. What a nightmare for the consumer! Monoprice incorrectly names every 5 Gb / s cable as USB 3.0, and every 10 Gb / s cable as USB 3.1. On the other hand, such names are more understandable to the user than official ones.

I do not run into Monoprice. I like their cables. But their huge range of USB-C cables perfectly illustrates the incompatibility problem. Almost all manufacturers and sellers have these problems.

Thunderbolt 3


Let us turn to an even more confusing topic. Mac owners from the start of sales in 2011 MacBook Pro are accustomed to the Mini DisplayPort connector, which operates as a graphics port and a data port. They were also used to pushing the Thunderbolt cable into the Mini DisplayPort connector, and finding that nothing was working.

The same experience awaits us with the new USB Type-C port:

• Not all USB-C ports have the same features. Many are designed only for data, some can do data and video, very rare data, video and Thunderbolt 3!

• Thunderbolt 3 requires a special cable. Although it looks exactly the same as a regular USB-C!

• Thunderbolt 3 devices look just like USB-C devices — regular devices with a USB-C cable are limited to 5 Gbps or less, but devices with Thunderbolt 3 transmit 40 Gbps PCI Express!

Thunderbolt 3 ports and cables must be backward compatible with USB 3.1 Type-C cables, ports, and devices. But they will work slower. Praise the creator for backward compatibility. This, by the way, is a simplification. In fact, Thunderbolt 3 is “Alternate Mode” for cable and Type-C port, just like HDMI. But in practice, Thunderbolt 3 is a USB 3.1 for USB-C superset, since there are no implementations of Thunderbolt 3 with support for only USB 2.0.

Therefore, owners of machines with Thunderbolt 3 support should be careful when buying devices and cables, so as not to fly with bandwidth. Most current Apple accessories and USB-C cables will work with the new MacBook Pro (it is backward compatible), but may not provide full speed. And the owners of the old 12 ″ Retina MacBook are even worse, because devices with Thunderbolt 3 will not work there at all!

Since Thunderbolt 3 includes data and video, you can easily get confused with the compatibility of computers, cables and devices. For example, a Thunderbolt 3 cable can support two 4K 60 Hz monitors, or even a 5K monitor, while the USB-C cable is limited to one 4K monitor. It's funny that USB-C Alternate Mode video compatibility is not the same as that of Thunderbolt 3. The latter supports HDMI 2.0, and USB 3.1 can only HDMI 1.4b. But in the case of DisplayPort, USB 3.1 will have an advantage, it supports version 1.3, and not just 1.2, like Thunderbolt 3. It all depends on the implementation on a particular machine.


Apple didn’t do the Thunderbolt icon on the new MacBook Pro, which has confused consumers even more!

Note that there are Thunderbolt 3 cables at both 40 and 20 Gb / s. And the MacBook Pro is not compatible with the first generation of Texas Instruments Thunderbolt 3 controllers used in many early Thunderbolt 3 devices!

My opinion


Given this insane level of “compatibility” for the new USB Type-C port, customers will have to be very careful. And if the fact that the industry is moving to a simple, reliable, two-way port for data, video and power is good - then this mess of devices and cables will upset consumers and get technicians.

Addition: if stuck, it should work


I received a lot of criticism of the original version of the article, and it is that everything seems to be not as bad as I describe. Basically, this is true as long as people have Nexus phones that support only USB, etc. But it seems to me that there is a problem with the many options for using this universal cable and port.

Electronics has ceased to be an area of ​​interest for geeks alone. Most computers, phones, tablets and peripherals are purchased by people who are not technically savvy. They do not distinguish the protocol from the interface and are not required to understand how “USB Type-C” differs from “Thunderbolt 3” or “USB 3.1”. They want to buy things, connect them, and so that everything works. They evaluate compatibility in form and matching of connectors, rather than specifications and logo.

Historically, the industry has coped with this. After the first roughness, USB became a boon to the average user. Cables, devices, peripherals - most of them just work. Although the experience of using USB 3, Mini USB, Micro USB and high-power charging is not perfect, waiting for the user “is suitable, it means it works” and today is true for USB. I myself am using a garland of cheap USB cables right now. And the reason is that USB was both a cable and a protocol. Apart from the power supply (how many iPads are slowly charging from iPhone cubes?), USB worked because USB is USB.

And now there is a "universal" cable that can become the only port on the device. Data, video, power - for only one USB Type-C port. And Intel switched to higher gear by adding a completely separate world of data and video support, Thunderbolt 3. It’s unrealistic to expect all ports, cables and devices to work correctly with each other, especially if it is much cheaper to make a device or a USB cable 3.1 gen 1 or even USB 2.0.

From now on (from the beginning of sales of Thunderbolt 3 devices) we have a port that does not meet the user's expectations. Cables are not compatible, devices do not support any peripherals, although the ports look the same. This is a nightmare: the consumer will pull the wrong cable out of the box, store or backpack, and decide that the device or charging is broken when it does not work. We will face disappointments, returns, and confused tech support.

This is an old compatibility story. We are improving compatibility in order to raise consumer expectations that everything will just work. But USB Type-C will never work, because USB-C is too many things at once. And this is a nightmare.

Also popular now: