Not enough screen on your Mac? Good news, it is possible to connect a second screen to it.
In this tutorial, we explain how to identify the adapter to connect your Mac to another display and how to set up your computer to detect it.
Note that since Sierra’s launch in September 2016, some third-party adapters appear to no longer work with Macs.
With Catalina (macOS 10.14), it is possible to use an iPad as a second screen, via Sidecar.
Recommended article: How to connect more than one screen to a MacBook Silicon?
Identify the ports on your Mac
The choice of adapter depends your Mac model and its ports. Here are the two main connection ports for Macs.
If your Mac model was released in late 2008 then it has Mini DisplayPort, using the appropriate adapter you can connect devices compatible with VGA, DVI and HDMI.
If your Mac was released in 2011, then it is equipped with the Thunderbolt port. If it came out after 2013, then it has Thunderbolt 2.
On the other hand if you have an iMac or Macbook Pro from 2016 or later then, you have a USB-C (Thunderbolt 3) port, see image below.
The latter does not allow you to use adapters, Mini DisplayPort to Dual Link DVI, Mini DisplayPort to DVI, Mini DisplayPort to VGA and LED Cinema Display.
Identify the ports on your external display
Now, you need to identify the outputs of your second screen, in order to find the adapter that can connect to it.
The port VGA has 15 pins distributed over 3 rows. It allows viewing HD videos with analog audio signal.
The exit DVI (24 pin) offers a much better display quality than VGA, the colors will be more nuanced. The difference is noticeable when you watch HD video.
Depending on whether it is DVI-A, DVI-D or DVI-I, the transmitted signals and the number of pins will not be the same.
The port HDMI (High Definition Multimedia Interface) is compatible with no less than 8 audio channels and is the most common on televisions. Its standard (HDMI 2.1) has a bandwidth of 48 Gbits / s.
Which cable to choose?
There are 6 different cables to connect your Mac to an external display. You can buy one from a third-party vendor where it will probably be cheaper.
However, as mentioned above, some have become obsolete. In order not to run the risk of incompatibility, it is better to turn to an Apple brand cable.
Also, note that the ports on Apple computers are female, so your cable will need to have male outputs.
Find below the different adapters you can use.
- USB Type-C to HDMI, to connect a Thunderbotl 3 Mac to an HDMI display.
- The Thunderbolt 3 (USB-C) to Thundebolt 2 Used to connect displays with a Thunderbolt port.
- The USB-C Digital AV multiport Connects your Mac to a projector or VGA display.
Note that it is not compatible with HDCP (High-Bandwidth Digital Content Protection) content. This standard provides copy protection for audio and digital streams. So you will need an HDMI output and cable.
- The Mini DisplayPort to VGA applies to VGA displays, for Macs with a Mini Display or Thunderbolt port.
- The Mini DisplayPort to DVI can be used to connect a DVI display to a Mac with Mini Display or Thunderbolt ports.
DVI is compatible with the HDCP standard. It is suitable for displays incompatible with DVI Dual Link resolutions (1920 x 1200 or lower).
- The Mini DisplayPort to Dual Link DVI is for DVI displays with resolutions of 1920 x 1200 minimum. To use it, your Mac must have a USB port.
Set up a second screen for your Mac
Once you’ve found the perfect fit, follow these five steps:
- Connect the adapter to your Mac.
- Open System Preferences → Monitors.
- Click on the tab Disposition.
- Leave the Video mirroring box unchecked, unless you want to see the same content as on your computer.
- Slide the monitors to the desired position. A white menu bar appears, indicating the main screen. Drag it onto the screen of your choice.
To copy the video to the two screens, follow points 1 to 4 given previously and check the box Video copy.
You can also select, at the bottom of the window, Show mirroring options in menu bar if applicable.
A status will be displayed in the menu bar, from which you can activate and deactivate the second screen.
If you have an Apple TV, you can use AirPlay as the 2nd screen to display your TV.
We have listed below the most common display problems with their solutions.
- If the cables and outputs match but your screen remains black, try restarting your Mac.
- If after the previous attempt nothing works then restart your computer in safe mode and restore default display settings.
- You can also try to adjust the brightness and contrast. For that go to System Preferences → Monitors, and change the resolution.
- If your Mac doesn’t seem to detect the external display, then go to System Preferences → Monitors. Hold down the key alt / option, then click Detect monitors.