Cast your minds back to the launch of the 27" iMac in mid-2009. One of the new features was Target Display Mode, which introduced the ability to use the iMac as a pure external monitor, bypassing the ...
An iMac feature that lets the screen function as an external monitor for another computer. Thunderbolt-based iMacs starting in 2011 can only be a Target Display Mode (TDM) screen for computers ...