Actually you are thinking of the NEC Multisync II,
model
JC-1402HMA. It can do CGA, EGA, VGA, and virtually any
other digital or analog RGB. I use one all the time, and
it has a beautiful picture to boot.
Can't do uninterlaced scan of much above 1024x768, and that only
at about 60 Hz vertical. But they are good monitors for things that
don't need extremely high resolution.
Almost all later multiscan-type monitors can't handle horizontal rates
*lower* than 31.5 KHz (VGA). :-(