HDTV is more than just digital TV. It's wide screen, high resolution digital TV with the most picture detail available in a broadcast signal. Regular digital TV gives you a 705 x 485 picture at best; HDTV delivers resolution as high as
1920 x 1080 (VOOM HD Originals, for example). When you see true HD, the difference is clear. Don't be fooled by providers who try to pass off their digital TV as HDTV.
http://www.voom.com/hdrc/fact_or_fiction.shtml
Then we have this:
VOOM is built to harness the most advanced methods of signal transmission, bringing you the highest quality HD and SD images in the industry.
Would not be 1920 x 1080i be the highest quality HD, not 1440 x 1080i .