The Multiple Scan 720 supports DDC (Data Display Channel) which is not supported on most Macintosh computers. By default, this control is set to "Off". However, if you have a Power Macintosh 9600 computer, a Power Macintosh G3 Tower, Desktop, or All-In-One, an IBM PC-compatible computer, or if you have a graphics card installed in your computer that supports DDC, additional resolution settings may be available by selecting a different setting.
To select a setting, turn the Select/Adjust knob to highlight one of the following options: 2B, 1/2B, or 2AB. Then press the Enter button.
This information is located in the Multiple Scan 720 User's Manual on page 27 under "Information: Mode, Absence, DDC".