Using Dual Monitors

If you are now working from home using a laptop but are accustomed to working on a desktop PC with a separate screen then you may find the laptop screen a little on the small side to be comfortable. Fortunately, most laptops allow you to connect to a separate, external screen.

If you have a separate computer monitor then you should be able to use this. Alternatively, most television screens from the last 10 years or so will have connectors at the rear that will allow a laptop to be attached.

This article details how to do this.

To connect your laptop to an external screen you’ll need a suitable cable between the two. There are a lot of different cables for this purpose so you’ll need to ensure you get the right one. To do this you’ll need to identify video connectors on both the laptop and the screen

Video Ports
A “port” is a generic name for a physical connector on computer (e.g. USB port, VGA port etc.). Most laptops will have one video port to connect an external screen. This will be one of several standard ports and depends upon the physical size of the laptop case and the date of manufacture. The video port will usually be located at one side of the laptop or, occasionally, at the rear of the laptop.

Video ports found on laptops

Laptop VGA Port
The VGA port is a 15-pin connector – either in black as shown or often coloured blue.  It is a relatively large connector so cannot be fitted to the most recent slimline laptop designs. A VGA port can only output a signal to an external screen that has a similar VGA port. You will need a VGA-to-VGA cable for this.

Laptop HDMI Port
The next most common port is the HDMI port, also found on domestic TV equipment. A standard HDMI connector is shown above (note the symmetrical shape). An HDMI port can output to an external screen with a similar HDMI port or one with a DVI port using a suitable cable.

There are 3 different sizes of HDMI ports available (see image). The smaller sizes may be used on a laptop to save space. All of these HDMI connectors output the same signal and all will connect to a screen with HDMI or DVI ports.

Laptop Display Port and Mini Display Port
The “Display Port” connector is similar to HDMI but is squared off at one side (i.e. asymmetrical).  There may also be a small “D” symbol next to the connector as shown top right. There Is also a “Mini Display Port” connector as shown lower right (this is commonly found on Apple MacBooks but also on some Windows laptop designs).

Display Port can output to an external screen with an HDMI port or a DVI port with a suitable cable.

Laptop USB-C Port
The most recent laptop video port is the USB-C connector (also known as “DisplayPort over USB-C”). This is a multi-purpose USB port that can also output video using the appropriate cable.

A “D” symbol beside the USB-C port indicates that it is can be used as DisplayPort and can output video.

So, these are all the video connectors that you are likely to see on your laptop. Have a look around the laptop and see which one is fitted to your device and this will determine the type of plug that will need to be fitted to the video cable at the laptop end.

Screen/Monitor Video Ports
The other end of the video cable will connect to the external screen. There are 4 possible connector types on screens, one of which is different to the other 3.

Video ports found on screens and monitors

The VGA connector is different from all the others in that you can only connect VGA to VGA. Note that the cheapest screens will only have a VGA port so you cannot connect HDMI, DisplayPort, or USB-C to these screens.

The other 3 connectors – HDMI, DVI and DisplayPort are all compatible with each other so you can connect these all together (e.g. HDMI to DVI, or DisplayPort to HDMI, or HDMI to HDMI and so on). You can also connect USB-C to any of these 3 connectors.

Now that you’ve identified the port types on the laptop and the screen, you just need to obtain a video cable with suitable connectors on each end. Alternatively, if you are purchasing a new screen, then ensure that it has a connector that will work with your laptop.

In simple terms, if the screen is described with only a VGA connector, then your laptop must also have a VGA connector for it to work. If the screen has DVI and/or HDMI then your laptop can have any of the connectors other than VGA and, with a suitable cable, it will work.

Below are a few examples of video cables readily available.

Video connecting cables

Setting Up Microsoft Windows for Dual Screens

Once you have your second screen and a suitable video cable, connect the two together and you should immediately see the laptop screen duplicated on the external screen. This works but you are not getting the most from this setup – the image on the external screen may also appear a little “blurry”.

You can get more from this setup by “extending the Windows desktop” across the two screens. This allows you to use both laptop and external screen as if they were combined together to form one larger, wider screen. You can drag windows to either of the two screens and see more whilst working.

To set this up you’ll need to configure Windows as follows. This document assumes you are using Windows 10.

Connect both screens and ensure you can see an image on each

Move the mouse cursor to an empty area on the desktop and RIGHT-click

Select “Display Settings” from this menu

From the popup menu (similar to that shown above), select Display settings near the bottom of the menu. This will open the settings window with options to control the Display as shown below.

Select “Extend these displays” from this menu

Now scroll down the display window until you see the Multiple displays option. This will probably be set to Duplicate these displays currently.

Click on the arrow to the right and select the option Extend these displays.

This will preview your selection. Select Keep changes

Now try moving the mouse across the two screens. If the mouse movement is wrong then you just need to tell Windows where each screen is positioned relative to the other (left or right). Scroll back up to the top of the Display Settings window to the Rearrange your displays option.

Drag the screens icons to reflect the position of your screens

Click on Identify to display the number of each screen (1 or 2).

Now drag the icons above the Identify and Detect buttons so that they are positioned correctly.

Author: Plus1Support

Owner of Plus 1 Computing - IT services for businesses and home users

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