What Is a Display Adapter?
A display adapter is a small conversion device that connects to a USB port or other general-purpose terminal on the main unit of a computer and outputs to a display terminal, such as HDMI.
This allows devices with few displays, such as notebook computers and tablets, to use multiple monitors to improve work efficiency and enjoy images on a large screen. A display adapter can also improve video quality, such as high resolution and high refresh rate, by converting video signals.
Display adapters attach to high-speed general-purpose ports such as USB 3.0 or Thunderbolt, but may require a power supply; in addition to general-purpose ports such as USB ports, some display adapters convert from one DisplayPort, such as VGA or HDMI to another such as DVI. Display adapters are available in a wide range of prices, depending on type and performance.
Display adapters vary in price depending on type and performance, but generally range from a few dollars to thousands of dollars; although they sometimes refer to drivers for graphics boards in PC operating systems such as Windows 10, we will discuss the former here.
Uses of Display Adapters
Display adapters are used to enable multi-display configurations on PCs with few display terminals. For example, by using a display adapter to output video to an external monitor on a laptop, tablet, or other device with few display terminals, multiple windows or applications can be displayed simultaneously, or separate tasks can be displayed separately.
In addition, if the display terminals of the PC and monitor do not match, they can be converted so that they can be connected.
Principle of Display Adapter
1. USB to DisplayPort
The USB display adapter converts USB to various display ports, and the USB display adapter’s dedicated software develops a virtual display in memory.
To reduce the amount of data transfer, the software compresses the difference between the screen changes and transfers it to the display adapter. The display adapter outputs the video signal to the connected display while decompressing.
2. DisplayPort → DisplayPort
In the case of display adapters used when the PC side is VGA and the monitor side is HDMI or DVI, display ports with different specifications not only have different port shapes but also different signal formats. Therefore, the display adapter appropriately converts the input signal from the image output port side to the port signal on the image display side.
Each DisplayPort has its own differences in output resolution, output frequency, audio input/output, and copyright protection. It is possible to convert a signal from a functionally less capable port to a more capable port, but the signal content will not be converted to match the functionality of the more capable port (a low-resolution image will not become a high-resolution image).
Types of Display Adapters
There are various types of display adapters, such as HDMI-DisplayPort and VGA-HDMI, depending on the communication standard to be converted to each other. The VGA-HDMI Display Adapter is often used to connect an older PC to a newer display.
Older PCs often have only VGA ports, which are an older standard, and must be converted to HDMI or other formats to connect to newer displays. In addition, an increasing number of recent notebook PCs have only USB Type-C output ports.
In such cases, a USB Type-C to HDMI or USB Type-C to DisplayPort Display Adapter must be used for external screen output. The advantage of USB-type display adapters is that they are USB bus-powered and do not require a separate AC adapter or other power supply.
Other Information on Display Adapters
Wireless Display Adapters
A wireless display adapter is a device that enables wireless communication between a PC and a display. By using a wireless display adapter, you can eliminate the hassle of physically connecting a PC to a display.
The wireless display adapter must be installed on both the PC and the display. Note that the screen and audio are compressed and transmitted in H.264 format during the wireless connection, which may degrade image quality.
In addition, delays are more likely to occur compared to a physical cable connection.