Depends on your outdoor condenser unit and your thermistat. If you have a two-stage compressor on the outside unit, like this http://www.simpsonsheetmetal.com/PDFs/38-tdb.pdf
it should operate on a low and high blower speed. If you also have a humidity control on the thermostat, like this thermidistat,
http://www.xpedio.carrier.com/idc/gr...lit/019113.pdf, it will slow down the blower on both high and low compressor if the humidity is too high, giving you four blower speeds. (sorry if the links don't work)