Adapters and Converters – CompTIA A+ 220-901 – 1.11

| December 4, 2015

As we install new systems or upgrade old ones, we often find problems connecting our hardware together. In this video, you’ll learn about many of the adapters and converters that you can use to connect video, network, and external peripheral devices.

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It inevitably happens. You get your computer and your network connection and your video all set up, and for some reason, you don’t have connectors that match up on these. So you’re going to need some type of adapter. This will allow you to convert between these different connector types. We just have to make sure that the conversion is one that is electrically compatible. Sometimes, you need to convert because you don’t have a particular port available. A lot of our newer laptops have USB connectors; they don’t have any ethernet connectors. So it’s very common, these days, to use a USB to ethernet converter.

This might just be a temporary fix, or it may be something you use permanently. Really depends on what the type of connection is, and what you need to use it for. A common converter for video signals is going from a DVI connector to an HDMI. It’s not uncommon to have a DVI connection on a video card, but have an HDMI connection on your monitor, or vice versa. These two types are electrically compatible. The HDMI is designed to be backwards compatible with these DVI digital connections. You don’t have to do any type of signal conversion, there’s no loss of video quality. This type of cable can be put in permanently, and you have no idea that you’re doing any type of conversion between these interfaces.

It’s very common to convert between USB connector types on the same cable. You can see that these cables do have a USB A connector and a USB B connector on them. The USB A connector is the standard-A plug. It’s usually the downstream port. This is usually the computer or the host device that you’re using, and it’s connecting to the USB standard-B plug. This is the upstream receptacle, and it’s usually the external device, like a printer or a USB interface. You can see the USB 3.0 standard A to B plug is here on the left, and the USB 1.1 or 2.0 standard USB A to USB plug is here on the right.

These two port types are electrically compatible with each other, so there’s no conversion necessary. You can send the same signal out of a standard A plug, and have that same signal arrive on the standard B plug. As our laptops are getting smaller and smaller, the manufacturers are choosing not to put some interfaces on the device themselves. You may often see, these days, that a laptop doesn’t have a physical ethernet jack on it any longer. Instead, they’re expecting you to use wireless. But what if you’d like to plug into a wired ethernet connection? One way to do this is with a USB to ethernet converter.

You’re converting from a USB connection on the laptop to an ethernet connection, an RJ45, on the converter itself. In this way, you’re able to connect to an ethernet network, even though you don’t have a physical ethernet jack on the laptop. One of the standards with DVI is the DVI-A. That is an analog signal being sent over a DVI interface. This is backwards compatible with VGA, but only resolutions at 640 x 480. You might need an adapter to fit onto the end of a VGA cable. Again, you’re going from a VGA analog to a DVI analog.

If you’re going from a VGA connection, which is an analog signal, to a DVI-A connection, which is also an analog signal, then you may only need an adapter. You can see an example of this here, where I have a VGA cable, and I’ve simply added on the DVI adapter to the end of it. If you’re going from this VGA analog connection to a DVI digital connection, you’ll need to perform some type of conversion process. You need to look at the specifications of what you’re connecting, to see what type of connector you’re going to need. Here’s one of the analog adapters. You can see VGA is on one side of the adapter, and on the other side is the DVI-A analog connection.

One relatively new interface type is the Thunderbolt interface. The Thunderbolt interface looks just like a Mini DisplayPort connector, but it’s carrying both DisplayPort video and PCI Express data. The DisplayPort signals on Thunderbolt are compatible with DVI-D digital connections, so you can simply have a connector that adapts the Thunderbolt connection to a DVI-D single link connector, and you don’t have to perform any type of conversion to send that video signal. Here’s a close-up of the two sides of this adapter cable. On one side is the Thunderbolt connector. You can see it is identical to a Mini DisplayPort connector. And on the other side is the DVI connection. So you can simply connect these two together, and now you’re able to send the video signal from one side to the other.

As the years have progressed, we’ve changed our keyboard and mouse connections from PS/2 connections to USB. But you may run into a scenario where a motherboard only has USB and you have PS/2, or vice versa. Fortunately, there are adapters for this. The PS/2 to USB adapters allow you to convert a mouse or keyboard interface from the PS/2 connection to the USB, or from USB back to PS/2. If you’re in a conference room, you may find that the conference projector will only receive VGA signals, but you might be using a device that sends HDMI. In that particular instance, you need an HDMI to VGA converter.

HDMI, of course, is digital only, and VGA is analog only. You can’t really mix those two without doing some type of conversion. So this cable or adapter is one that is performing a conversion between the HDMI digital and the VGA analog. You’ll sometimes see this referred to as an active converter cable. You can’t simply connect the two, and expect them to work. There has to be some type of conversion in the middle. This will ideally convert video. Optionally, some of these converters will also convert the audio that’s coming from the VGA, and output it onto a separate connector at the end of the cable.

Here’s a closer look at this conversion cable. You can see the HDMI digital on one side, and the VGA analog on the other. This particular converter did not have the audio function, but if it did, there would be a separate interface on the side of the cable to use to plug-in your audio connection.

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Category: CompTIA A+ 220-901

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