This is what you need to know about USB connections

USB, or Universal Serial Bus, was once developed to simplify the complex world of connections to your PC. They have never really succeeded in that mission, because USB itself now comes in many shapes and sizes, and sometimes even cables that seem identical are different inside. How do you know which USB connections you need? We help you!

Tip 01: Plugs and protocol

The idea behind USB was very good and it still is. However, the reality is that with so many different manufacturers making hardware and so many different interests, it's really not possible to make something that fits anywhere and everywhere. The difference between USB cables is not only in the plugs, but also in the protocol behind them. So you can have two apparently identical cables, which also fit fine on the same port, but where one cable is a USB1 cable, and the other a USB3 cable, with a significant difference in speed. This example only shows what a maze the world of USB has become.

Tip 02: ABC

We'll start with the basics, which is the physical plug that attaches to the USB cable. Roughly speaking, we now distinguish three different types of plugs, in terms of shape. Starting with usb-a. Everyone knows this type of cable, because this is the part that you plug into the front or back of your PC. The plug you'll find on the other side of the cable is likely a USB-B cable if it's a printer cable, or a micro or mini-USB cable if it's a cable for other peripherals. Nice detail: the main reason that USB-B exists is to prevent people from having cables with two USB-A plugs in their homes, because this could be used to connect two PCs to each other. And that is not without risk. Finally, there is also usb-c, this is a relatively new type of plug, and again a (failed) attempt to make usb universal. The plug is much smaller than that of usb-a, and designed in such a way that there is no top or bottom, so you can't put the plug in the wrong way.

Roughly speaking, we distinguish three types of plugs in terms of shape: usb-a, usb-b and usb-c

Tip 03: 123

In addition to the shape of the plugs, USB also has to do with protocols, i.e. the technology used. Take, for example, two cars. They may look exactly the same, but if one has a more powerful engine than the other, their performance will be significantly different. This also works with USB. In 1996 USB 1.0 was launched, over which data could be transferred at a speed of 1.5 Mbit/s. The successor, USB 1.1 in 1998, already did that with 12 Mbit/s. USB 2.0 followed in 2000, with a maximum speed of 480 Mbit/s, followed by USB 3.0 in 2008, with a maximum speed of 4.8 Gbit/s. USB 3.1 was released in 2013, increasing the maximum speed to 10 Gbit/s. The most current protocol dates from 2017, with a maximum speed of 16 Gbit/s. Clear, fine and clear, right? In theory yes, were it not for the fact that except for USB 3.1, all these protocols basically use the same USB-A plug, with, at most, a different color to distinguish it. And since the principle of the weakest link applies here (a usb3.0 plug connected to a usb1.0 port is limited to the speed of that 1.0 port), the potential of usb has been all but exploited over the years. .

In addition to the speed, the different versions of USB also have differences in power transfer. For example, USB 1.1 can supply 2.5 V of voltage, with a current of up to 0.5 A and a power of 1.25 W. USB 2.0 is equal in amperes to USB 1.1, but supports 5 V and a power of 2. 5 W. With the exception of usb-pd (see tip 8) the voltage of all subsequent usb protocols remains the same at 5 V, with the difference that usb 3.0 and 3.1 support 0.9 A and 4.5 W and usb-c 3 A and 15 W. Lots of numbers, but what's especially important to remember from this story is that the amp determines how fast a smartphone can be charged. And for much-needed context: wattage = amps x volts. So if you know the wattage and voltage of a charger, you can calculate the ampere.

Tip 04: Micro and mini

Now that you know that there are USB 1.0, 2.0, 3.0 and 3.1, and a, b and c, let's make it a little more complicated. You have already briefly seen micro and mini in tip 2 in combination with usb-a and usb-b. Micro USB is the smallest plug in the range. You can recognize this by the small, flat plug that resembles a very small HDMI cable. In most cases, a micro-usb plug is usb-b. Usb-a is not very common in micro form. Mini USB is also a small plug, but thicker and narrower than micro USB. And mini-usb is always in the form of usb-a. And that sometimes makes it so unnecessarily complicated: micro-usb and mini-usb are two separate categories with the subdivision a and b. To get a headache.

Tip 05: Thunderbolt

Thunderbolt is a type of cable that originated from a collaboration between Apple and Intel. Thunderbolt was once designed to wipe USB off the card as a universal connector. That didn't work, but Thunderbolt is four times as fast as USB 3.0, making a data transfer of 40 Gbit/s possible. The reason we take a trip to Thunderbolt is because Thunderbolt 3 uses the USB-C plug. That seems like a fantastic development, were it not for the fact that not all USB-C ports support Thunderbolt 3. That should be specifically marked, with a lightning bolt icon. It is important that it concerns the thunderbolt protocol and not the thunderbolt plug. A thunderbolt-1 or -2 plug simply won't fit into a USB-C port.

Tip 06: Adapter cable/docks

It's a nice thought that whatever connection you have on your PC or peripheral equipment, there is always an adapter cable available so that you can connect the devices with each other. The only thing is that you have to take into account the limitations of the protocols that the technology works with. As indicated earlier: if you use an adapter cable to connect a USB-C drive to a USB-A port, the speed will not exceed the speed of the USB-A port. This situation also applies to docks. You can connect a dock to your PC so that you can connect USB-C plugs to a laptop that naturally only supports USB-A, but you will never achieve the speed of USB-C. Moreover, with the arrival of USB-C, another complexity has been introduced. Because even if you connect a usb-c cable to a usb-c connection, you have no guarantee that you can use all the possibilities that the device or the connection offers. Within the different types and protocols, different modes also play a role. It's sad how complicated it has all become.

Tip 07: Alt Mode

To continue on those different modes of usb-c, Alt Mode is one of them. That consists of HDMI Alt Mode and DP Alt Mode. In short: HDMI Alt Mode is used to send HDMI signals over the USB-C connector without the need for a converter to convert the signal. DP Alt Mode, or DisplayPort Alt Mode, makes it possible to connect displayport equipment via USB.

What it basically means is that computer manufacturers no longer have to equip their desktops and laptops with specific HDMI and DP ports, but that everything just goes via USB and the mode ensures that the signal is delivered correctly. However, and you can feel it coming, not all USB-c ports support Alt Mode. A laptop or desktop with a USB-C port that supports Thunderbolt also supports Alt Mode. The same goes for usb-c 3.1 generation 2 (yes, so there is also a second generation), but if you want to know if Alt Mode is supported, just look at the specifications of the usb port.

Tip 08: Power Delivery

We see more and more laptops that do not seem to have a specific charging connection, but that can simply be charged via the USB-c port. Seems, because in reality you can't just charge a laptop via any USB-c port. For this it is important that the usb-c port (and the device you use to charge the laptop with) supports pd, which stands for Power Delivery. A standard USB-C port will handle a maximum of 3 amps with a maximum of 5 volts, but with Power Delivery, the USB port and the device connected to it (the charger) agree together how much current is allowed to pass through the cable. A USB-C port with Power Delivery can handle up to 5 amps with a maximum of 20 volts. With Power Delivery you can charge a device much faster. Although there is also a considerable risk involved, which you can read more about in the next tip.

In reality, you can't just charge a laptop through any USB-C port

Tip 09: Resistance

You know that when using adapter cables, the weakest link is leading. However, the arrival of usb-c has ensured that using the wrong adapter cable can damage both the computer and the peripherals that are connected to it. A high-quality adapter cable from USB-C to USB-A has a small resistance on board (usually 56K ohms) so that (in combination with some other hardware) the peripherals will never demand more power than a port can supply. However, if you have bought a cheap cable that does not use resistance, it can happen that a smartphone that you connect to the laptop via USB-C to USB-A requires 3 amps of power, while the laptop can only supply 2 amps, so that you can irreparably damage your hardware. The internet is now full of stories of people who have suffered thousands of euros in damage in this way.

Tip 10: USB IF Certification

How do you know if you have a safe cable, with resistance, in your hands? Not ordering from cheap Chinese websites is a good start in our opinion, but there are examples of such incidents that have occurred with cables from manufacturers that you should expect to be all right. However, the difference is that if you buy a cable from a reputable brand and it damages your hardware, at least you still have somewhere to go with your claim. Fortunately, there has been a quality mark for some time that indicates whether a cable meets the correct specifications. When purchasing an adapter cable, verify that it meets the specifications for safe use by looking for the usb IF logo. IF stands for Implementers Forum, which is a non-profit organization dedicated to the promotion and support of usb. In addition to the fact that a cable with the usb IF logo should be safe, this quality mark also requires that each cable mentions exactly what the possibilities are and which protocols are supported. In the long run, this should at least remove some of the complexity surrounding USB.

Buying tips

Normally we always mention a few examples of products that are worth considering, but buying tips in the field of USB cables is of course slightly different. We have therefore highlighted three types of handy cables.

Type: Samsung Usb A to Usb C Cable

Price: € 16,99

In this article, we briefly mentioned the risk of connecting the wrong USB-C adapter cable. Therefore, do not save on such a cable and buy one from a reputable brand, such as this one from Samsung.

Type: Apple Thunderbolt 3 Cable 0.8 m

Price: € 45,-

Forty-five euros for a cable? Well, it is an Apple product of course. There are also copies of other brands, but they are not even that much cheaper. If you want to get the most speed out of your laptop and storage device (and they both support Thunderbolt), we recommend investing in this cable.

Type: Hyper USB-C Adapter With Thunderbolt 3

Price: € 91,99

You can invest in adapter cables for your MacBook, but we advise you to go for a dock in such a case. Various docks are available, each with its own set of ports, such as this dock with hdmi, usb-c and usb 3. There are also docks available for other models of laptops.

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