This article is from the Macintosh hardware FAQ, by Elliotte Rusty Harold elharo@shock.njit.edu with numerous contributions by others.
A IIsi, LC or LC II can drive a multisync/multiscanning VGA monitor
with a simple cable adapter available at any Apple dealer for about
twelve dollars. You cannot use a fixed-frequency (i.e. cheap) VGA
monitor with these Macs since their internal video can't generate the
standard VGA frequency. Later Macs with built-in video work
perfectly with any VGA monitor with just a cable adapter. (Whether
the monitor works perfectly is another question.) The IIci is the
only Mac with built-in video-out that absolutely cannot drive a VGA
monitor.
 
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