The basic DTV converters have both QAM and ATSC tuners. They output 480i to non digital TVs
HD ready means the TV is older with analog tuners only or newer with no tuners (a moniter) but can display 1080 & 720 HD signals. They do not allow you to receive digital or HD signals over air or otherwise. They work in conjunction with Satellite, Cable, or OTA HD digital tuners and other external devices. HDTV has at least an ATSC tuner (over air). Most if not all current HDTVs have ATSC, NTSC (analog) and QAM (cable) tuners.
HD ready means the TV is older with analog tuners only or newer with no tuners (a moniter) but can display 1080 & 720 HD signals. They do not allow you to receive digital or HD signals over air or otherwise. They work in conjunction with Satellite, Cable, or OTA HD digital tuners and other external devices. HDTV has at least an ATSC tuner (over air). Most if not all current HDTVs have ATSC, NTSC (analog) and QAM (cable) tuners.