Does a low page limit (3 pages) indicate anything about the quality of a conference? I'm concerned about a scientific &amp; tech. conference which has set the page limit to 3!

I'm wondering if that means the quality of submitted paper in this conference is considered low.

What do they expect from authors to put into 3 pages?
Do not confuse quality and quantity: the two dimensions are orthogonal.

A 3-page limit means that the conference is really asking for extended abstracts, rather than full papers.  You can't say much in a 3-page extended abstract, even in the highly dense IEEE two-column format, so it can't be treated the same as a full paper, but that's not reason for it to be bad, just terse.  The conference might well attract very high quality 3-page extended abstracts.  One thing that some such conferences do is have an associated journal special issue, where full papers are later invited.