Using Your iMac as a 2nd Display

Target Display Mode is a feature supported by select iMac desktops that enables an iMac to be used as an additional display for another Mac. The beauty of Target Display Mode is that it allows you to leverage your existing Mac devices to support a multi-display arrangment for tasks that might be better suited for a larger screen. Compatibility is very specific to certain models and the cable required is dependent on the generation of iMac. More recent models of the iMac (Retina 5K, 27-inch, Late 2014) and later iMac models do not support this feature at all. Also, the iMac must be using OS X 10.6.1 or later.

Target Display Compatibility

iMac Model Cable Required Port Required on Source
iMac (only 27-inch Late 2009) Mini DisplayPort Mini DisplayPort or Thunderbolt 2
iMac (only 27-inch Mid 2010) Mini DisplayPort Mini DisplayPort or Thunderbolt 2
iMac (Mid 2011, both 21.5-inch and 27-inch) Thunderbolt 2 Thunderbolt 2
iMac (Mid 2012- Mid 2014, both 21.5-inch and 27-inch) Thunderbolt 2 Thunderbolt 2

Cables

The only supported cables for this feature are Mini DisplayPort or Thunderbolt 2, depending on the configuration as listed in the table above. Mini DisplayPort and Thunderbolt 2 share the same dimensions for port size and connector, however, the technology for each is very different. A Thunderbolt 2 cable can support all the functions of a Mini DisplayPort cable (and can use the same port) in addition to transmitting data and is compatible with exertnal devices like external hardrives. A Mini DisplayPort cable is an Audio/Video cable only and can only be used to transmit video and sound to a display. 

Cable Matters carries a variety of both types of cables which can be found by following the linked products below:

Product #107001 Thunderbolt 2 cable - Available in White or Black in 3.3, 6.6, or 9.8 foot lengths

Product #101008 Mini DisplayPort cable - Available in White or Black in 3, 6, 10, and 15 foot lengths

Enable Target Display Mode

Fortunately, using Target Display Mode is very straight forward:

  1. Turn on both computers
  2. Connect the appropriate cable between the two computers
  3. Press Command-F2 on the keyboard of the iMac that will be the 2nd Display

After you press Command-F2, your iMac will display the desktop from the connected Mac. You can then chose to Extend or Mirror/Duplicate your screen from the Display menu.


Apple is a trademark of Apple Inc. Thunderbolt and the Thunderbolt logo are trademarks of the Intel Corporation in the U.S. and/or other countries.

Have a question or need more support for your Cable Matters product? Contact us at support@cablematters.com!



Article ID: 50
Last updated: 12 May, 2016
Revision: 16
Computer Accessories -> Using Your iMac as a 2nd Display
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