Isn't your Mac screen enough for you? Good news, it is possible to connect a second screen.
In this tutorial, we explain how to identify the adapter to connect your Mac to another screen and how to configure your computer to detect it.
Note that since the launch of Sierra in September 2016, it seems that some third-party adapters no longer work with Macs.
Identify the ports on your Mac
The choice of adapter depends on the model of your Mac and its ports. Here are the two main Mac connection ports.
If your Mac model was released in late 2008, then it has the Mini DisplayPort, using the appropriate adapter, you can connect devices compatible with VGA, DVI and HDMI.
Mini Display Port
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.
Thunderbolt port
On the other hand if you have an Mac i or a Macbook Pro dating from 2016 or later then, you have a USB-C port. The latter does not allow you to use adapters, Mini DisplayPort to DVI dual link, Mini DisplayPort to DVI, Mini DisplayPort to VGA and LED Cinema Display.
USB ‑ C port (Thunderbolt 3)
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 15-pin VGA port distributed in 3 rows. It allows you to watch HD videos with an analog audio signal.
The DVI output (24 pins) offers a much better display quality than VGA, the colors will be more nuanced. The difference is noticeable when watching HD video.
Depending on whether it is a DVI-A, a DVI-D or a DVI-I, the transmitted signals and the number of pins will not be the same.
The HDMI port (High Definition Multimedia Interface) is compatible with no less than 8 audio channels and is the most common on televisions. Its new standard (HDMI 2.1) has a bandwidth of 48 Gbits /s
However, as mentioned above, some have become obsolete with macOS Sierra. To avoid the risk of incompatibility, it is better to buy a cable from the Apple brand.
Also, note that the ports on Apple computers are female, so your cable should have male outlets.
Find below the different adapters that you can use.
The Thunderbolt 3 (USB-C) to Thundebolt 2 (59 €) is used to connect displays with a Thunderbolt port.
The USB-C Digital AV multiport (79 €) allows you to connect your Mac to a projector or VGA screen.
Note that it is not compatible with HDCP (High-Bandwidth Digital Content Protection) content. This standard provides copy protection for audio and digital streams. You will therefore need an HDMI output and cable.
The Mini DisplayPort to VGA (35 €) concerns VGA screens, for Macs equipped with a Mini Display or Thunderbolt port.
The Mini DisplayPort to DVI (35 €) can be used to connect a DVI screen to a Mac with Mini Display or Thunderbolt ports.
DVI is compatible with the HDCP standard. It is suitable for screens incompatible with DVI Dual Link resolutions (1920 x 1200 or lower).
The Mini DisplayPort to DVI double link (119 €) is intended for DVI screens with resolutions of a minimum of 1920 x 1200. To use it, your Mac must have a USB port.
Set up a second screen on your Mac
Connect the adapter to your Mac.
Open System Preferences → Monitors .
Click the Layout tab .
Do not check the Video Copy box , unless you want to see the same content as on your computer.
Slide the monitors into the desired position. A white menu bar appears, used to indicate the main screen. Drag it to the screen of your choice.
To copy the video on the two screens, follow points 1 to 4 given above and check the Video Copy box .
You can also select Show video copy options from the menu bar . 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 2 nd screen to display your TV.
Display issues
We have listed the most common display problems and their solutions below.
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 the default display settings.
You can also try to adjust the brightness and contrast. To do this go to System Preferences → Monitors , and change the resolution.
If your Mac does not seem to detect the external screen, then go to System Preferences → Monitors . Press the Alt key , and finally click the Detect Monitors tab .
