After installing the Fusion HDTV, you will be asked to search for new channels. This can be done through an autoscan which will search both Over-The-Air (analog and digital) and cable (analog and digital). With the QAM version of the card, an additional selection is placed at the bottom of the screen. Here is where you need to select either QAM 64 or QAM 256. Quadrature Amplitude Modulation (QAM) is what most CATV companies use to transmit digital cable stations. Though it sounds complicated, this modulation technique is just a combination of two existing techniques, phase modulation and amplitude modulation. Binary numbers can be represented by both the "height" of the sine wave (amplitude) and the phase of the sine wave (+ or -). This allows for a more efficient method to transfer data. Without going into details (details which I myself am unsure about) QAM-256 can cram more data into its bandwidth than QAM-64. However, QAM-256 requires a much better carrier to noise ratio than QAM-64. Thus, you should check with your local cable company to see which modulation scheme is being used. Over-The-Air broadcasts use 8VSB modulation as set by the ATSC, Advanced Television Systems Committee. Using QAM modulation for Over-The-Air signals would result in unreliable data reception given the non-controlled environment of the media. While thinking about all of this can start to tie your brain cells in a knot, the main thing to take away is that the Fusion III QAM can decode all of these signal.