USB to HDMI Conversion


USB to HDMI Conversion

Connecting a high-definition television to a computer is something that many people have considered, but not been sure they could do. For many people, this may be a great option, providing them with a way of streaming content, such as photos and videos, from their computer through their home television. However, there are some barriers which make it hard to do this.

The HDMI connector is a 19 pin connector, while USB is only four pins. So, there is no way of wiring the two together through a homemade adapter cable. The data format for the two is considerably different as well, so even if you could get the right wires connected together, the information being transferred from the computer wouldn’t be understood by the television.

However, all is not lost. While the two don’t necessarily speak the same language, it is possible to translate from one to the other. All it takes is the right sort of translator; one which understands both languages.

Monitor and Television Resolution

In actuality, modern HDTV (high definition television) came out of computer technology. Most flat screen LCD or LED computer monitors manufactured today have the same resolution as 1080p. These high resolution monitors were first created for computers, and then the correct interface was added to them to make HDTV.

When we look at a number like “1080p,” what does that mean? It is telling us the amount of resolution that the screen has. This number refers to the number of vertical pixels on the screen. To put it into the language of broadcast TV, it is the number of lines of vertical resolution. Today’s HDTV uses one of two formats:


  •  720p, which is 1280 pixels wide by 720 pixels high
  • 1080p, which is 1920 pixels wide by 1080 pixels high

Before HDTV, what was known as “broadcast TV” had only 480 vertical lines of resolution. What we call 480p now. Several things happened to change that, amongst them being the change from a 4:3 aspect ratio to a 16:9 aspect ratio. This was done to accommodate the motion picture industry, which has long used a 16:9 “widescreen” aspect ratio for the creation of movies. As people were viewing more movies on their computers and televisions, the electronics industry saw the need to match their products to this format.

The other big thing that happened was that computer monitors became larger, with smaller pixels, which were packed tighter together. Whereas an original VGA monitor only had 640 x 480 pixels of resolution, today’s computer monitors are mostly 1080p (1920 x 1080 pixels).

So, the video which is being seen on the computer and the video which is being seen on the HDTV are compatible as far as format and resolution are concerned. All that is needed is to get them to talk to one another.

HDMI Computer Video Cards

DVI (digital video interface) has largely replaced VGA as the connection of choice between a computer and a monitor. Most new monitors are built with both VGA and DVI connectors on them. New computers are built with either both VGA and DVI outputs or just a DVI output.

DVI and HDMI are largely compatible. There are adapters which allow physical connection of one to the other, without any sort of device to translate the signal. However, HDMI carries audio signals as well as video, while DVI only carries video signals.

One way of connecting a computer to a HDTV is by installing a HDMI graphics card. This would replace the standard graphics card, sending the computer’s video output signal to the television via a HDMI connector on the back of the computer. However, doing so would eliminate the ability of connecting the computer to a standard computer monitor, unless the graphics card had both DVI and HDMI connectors on it. While some cards do have both connectors, not all do.

This would not work for a laptop computer. While some newer laptops already have a HDMI connector on them, not all do. All older laptops had a VGA connection for output to a separate monitor, rather than the newer HDMI.

USB to HDMI Adapters

The solution is to use a USB to HDMI adapter. These plug-and-play devices receive the audio and video signal from the computer, via the USB port, and convert the signal to HDMI format. A standard male-to-male USB cable is used to connect the device to the computer’s USB port and a standard male-to-male HDMI cable is used to connect the device to the HDTV.

These adapters will only work with a USB 2.0 port. The older USB 1.0 and 1.1 did not have a fast enough data throughput to carry both audio and video signals. The device receives its power from the USB port, eliminating the need for any further power supply.

Please note that the computer must be located relatively close to the HDTV when this is being done. Category 1 HDMI cables can only be used for up to 5 meters (15 feet) and Category 2 HDMI cables can only be used for up to 15 meters (49 feet).

There are also wireless USB to HDMI adapters. The wireless dongle is connected to the computer’s USB port, and the receiver is connected to the HDTV via a standard HDMI cable. These allow wireless connection for up to 30 feet. Please note that as with any wireless device, there is a higher possibility of both pirating and interference than there is with a hard-wired connection.


Rich Murphy