Peripheral Cables – CompTIA A+ 220-1101 – 3.1

USB isn’t the only way to connect our peripherals. In this video, you’ll learn about the many USB standards, Thunderbolt connections, and legacy serial console cables.

One of the most common methods of connecting peripherals to our computers is by using USB, or the universal serial bus if you’re connecting a mouse, a keyboard, a printer, or almost any other peripheral, you’re probably using USB. One of the early versions of USB was USB 1.1, and it had two different speeds. It had a low speed, which was 1.5 megabits per second and a maximum cable length of around 3 meters, and there was also a full speed version of USB 1.1, which supported 12 megabits per second over a maximum cable size of 5 meters.

Well, upgraded from USB 1.1 to USB 2.0 and increased the total maximum speed to 480 megabits per second over the maximum 5 meter cable size. USB 3.0 is an upgrade to USB 2, and sometimes you’ll see it referred to as super speed USB. It supports 5 gigabits per second over what usually is about a 3 meter cable. The USB 3.0 standard doesn’t specify a maximum cable length, but 3 meters is one that’s relatively common.

Some common connectors from the USB 1.1 and 2.0 versions are the Standard-A plug, which is very similar to the standard-A plug you would find on most devices, the much larger standard-B plug, and then especially on mobile devices, we use the mini-B plug and the micro-B plug. USB 3.0 change the connectors a bit to be able to support these higher speeds of throughput. The USB 3.0 standard-B plug is much different than the USB 2.0 version, although the standard-B plug does look very similar in size and shape. The USB 3.0 micro-B be plug though is very different than the USB 2.0 version.

In recent years, we’ve started to roll out a new type of connector for USB, called the USB-C connector the USB-C connector is very different than the A connectors that we’re used to using where you have to plug them in on exactly the right way to get them to work. With USB-C we simply plug-in the connector and there is no top or bottom it will work in either orientation. USB-C describes the connector itself, and does not describe the type of signal that you’re sending over that connection. And, indeed, over USB-C, you can send many different types of connections that are not only related to data, but you could also send video and other signals as well.

The USB-C connector is also quite small. You can see the standard-A plug on the right side, and the traditional micro-B plug on the left side. The USB-C plug is slightly larger than the micro-B, but not by much. And you can see that it is symmetric, so That it’s able to work with any orientation.

As the USB standards change, we’re also changing the names of how we refer to these different connections. So each time there’s an update to USB, all of those connection types are renamed to meet the new standard. If you’re looking at the USB 3.0 standard, that is referred to as the super speed connector, and it has a maximum speed of 5 gigabits per second.

We released an update to USB 3.0 called USB 3.1. That update changes the name of USB 3.0 to USB 3.1 gen 1. It’s still superspeed USB. It is still 5 gigabits per second, but in this new standard it has the new name of USB 3.1 Gen 1. USB 3.1 then is technically called USB 3.1 Gen 2, or superspeed plus, and it supports a maximum throughput that is double the USB 3.1 Gen 1 or 10 gigabits per second.

A new version of USB was released in September of 2017, and that version is USB 3.2. This effectively doubles the bandwidth available in USB and uses USB C connectors to be able to provide that throughput. This standard uses an extra lane of communication inside of that USB-C cable to provide that enhanced throughput.

And because this is a new standard, we have renamed all of the old standards. So the standard that used to be USB 3.0, which we change to USB 3.1 Gen 1 is now called USB 3.2 Gen 1 or superspeed USB 5 gigabits per second. Obviously, the speed hasn’t changed but the name of the standard has changed in USB 3.2. USB 3.1, which we were calling USB 3.1 Gen 2, is now called USB 3.2 Gen 2, and it of course, supports exactly the same speeds of throughput.

USB 3.2 Gen 1 times 2 is effectively using twice the number of Gen 1 lanes to provide 10 gigabits of throughput. There’s also a USB 3.2 Gen 2 times 2. The USB 3.2 Gen 2 is a 10 gigabit per second throughput, so when you double that throughput with the additional lane, you have a maximum of 20 gigabits per second.

So here’s the summary for USB 3.0, USB 3.1, and USB 3.2. You can see all of the standards with the old names and 3.0 and 3.1 are in this chart, and the USB 3.2 names are listed on the left side, along with the names, the speeds and the logos that are used for those standards.

Another common peripheral connection type is a Thunderbolt connection. This is a high speed serial connection that is able to put data and power on the same cable. Sometimes you’ll see these early versions of Thunderbolt using this mini DisplayPort as the physical connection type. Thunderbolt version 1 is a two channel technology and you can put 10 gigabits per second over each of those channels for a maximum throughput of 20 gigabits per second.

There’s also a Thunderbolt version 2 which has aggregated those channels together giving you a total throughput for anything connected to that Thunderbolt version 2 of 20 gigabits per second. With Thunderbolt version 3, we’re taking advantage of the USB-C connector and sending Thunderbolt signals over that USB-C cable. This provides us with a total aggregated throughput of 40 gigabits per second.

Thunderbolt signals can be set over both copper or fiber connections. If you’re using copper you have a maximum cable length of 3 meters, and if this is an optical or fiber connection, you’re running 60 meters in length. You can also daisy chain six different devices together. So you might have a single Thunderbolt interface on the back of your computer, but all of your peripherals may have multiple Thunderbolt interfaces, so that you can simply extend to six different devices by simply adding additional cables between all of those different peripherals.

Before we had a universal serial bus, we were using nine pin and 25 pin serial connections on our computers to be able to connect peripherals. These were commonly used to send RS-232 signals which would allow us to send serial communication between our computer and other devices, such as a modem. This is a standard that’s been around for such a long time that it’s very common to still find DB-9 or DB-25 connectors on different devices. This is commonly used these days to connect to serial consoles that might be on a peripheral device. So if you’re plugging in a switch, a router or firewall, you might use one of these serial console cables to connect to the device and be able to configure that device from the command line.