My father and I are now both using 27" iMacs with second Dell monitors. Mine, a 23" Dell (IIRC, the model number is U2311; it's the newer 23" IPS display), is connected using a Displayport -> Mini ...

Two of the most common video interfaces for transferring high-quality audio and video signals from an output device to a display are DisplayPort and High-Definition Multimedia Interface (HDMI). These ...