DTV conversion concerns

Question

What is necessary to make my "HDTV capable" 2 year old set recieve true digital signals? Are the converter boxes available now capable of recieving and transferring the proper signal or are they just as the name implies 'Converters" which change the digital siganl to analog and supply it to the set? At the time of purchase I was assured that this particular unit would function with only the addition of a digital tuner box once the switch was completed. Did I get suckered?

Samsung DynaFlat HD HDTV 1080i
Model ~ TX3271HFX / XAA