Remember Sesame Street? "This program is brought to you by the letter..." Well, it's back, but this time for digital TV. And digital TV is brought to you by the letters "i" and "p".

You'll see them next to numbers like 720 and 1080 when buying a TV set -- 720p, or 1080i or 1080p.

"i" and "p" have to do with how your TV set will make pictures.

First, "i". "i" stands for "interlaced," just like the laces on this tennis shoe -- one lace, then the other, then the other, over and over. An interlaced picture means you get one lace -- that's every other line -- and then the other lace, the missing lines -- to make a whole picture. It happens in 1/30th of a second, so fast your eye can't see it. That's "i." Interlaced. The TV set you've had all these years is an "i."

Now, "p". "p" stands for progressive, and it's just like the dinner party -- one thing after the other. So the picture comes into your TV set line by line, in order, 1, 2, 3, and 4, to make the picture. It does it in 1/30th of a second. That's "p." Progressive.

When you buy a set, you'll have a choice of "i" or "p".

Here's the quick version: according to the books, "p" is better than "i." "p" also costs more than "i."

But according to several consumer surveys, when they put the "i" and "p" through a side-by-side comparison, here's what they found: if the set's smaller than 50 inches, most people couldn't really see a difference.

Here's a quick way to see if it makes a difference to you. When you're in the store, watch an "i" and a "p" set side by side. When you see electronic letters on the screen -- like this -- look for letters with curves. Look closely at those curves. In theory, an "i" set will give you edges more jagged than a "p" set. Does that bother you? Well, that's up to you -- what your eyes perceive as better and what your wallet perceives as doable.

Here's one way to remember the difference between "i" and "p" -- "i" is for "inexpensive" and "p" is for -- prettier and pricier.

And here's something to make it even easier -- some major retailers have decided not to sell any "i" sets at all.

So, that's what those little "i" and "p" letters mean...

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For more information about ETV's Digital Television Services, contact:
Hap Griffin, Vice President, ETV Engineering
E-mail: Hap Griffin (hgriffin@scetv.org)
Office: (803) 737-3500