RT stands for cathode ray tube, the common picture tube used in TV sets for decades and still the most common display type today. Newer display types like Plasma and LCD work differently and aren't as large or heavy as the CRT, but the picture isn't necessarily any better.
CRT produces its pictures from a ray of electrons emanating from a cathode in the neck of a picture tube. The ray strikes the inner face of the picture tube, which is coated with lines of phosphor that light up when struck by the electron beam. The scan line offers resolution greater than most LCD, plasma or DLP displays. For a fixed pixel display to equal a CRT running 1080i, a resolution of 1920x1080 would be required. Only the most expensive LCD or plasma displays can reach this resolution.
Advantages of CRT
1.Over 50 years of engineering experience in CRT.
2.CRT TV sets are reliable and have a long life.
3.CRT rear-projection HDTVs are the least expensive large-screen TV.
4.1080i is equal to a fixed pixel resolution of 1920x1080.
5.Direct-view CRT is still the all-around best picture of all display types.
6.CRT TV is inexpensive and better than ever before.
Disadvantages of CRT
1.CRT's are the biggest and heaviest of all TV types.
2.Direct-view picture tubes have a size limitation about 36".
3.CRTs use more energy and generate more heat than DLP or LCD.
4.Rear-projection TVs have limited brightness when viewing at an angle.