hi def tv questions

[sublime]

just got my plasma and cox cable hooked up today. wondering about a few things.

when i first turned the TV on, the picture was surrounded by GRAY on the left and right. i went to NBC (which was hif def CFB iirc) and the same thing. i then pressed the HI DEF ZOOM button on my controller and zoomed the gray away.....doest seem right though? whats the deal here?

fwiw, i was over somebodys house the other day and when i asked him why his TV had gray edges he said "the channel is not hi def"

the gray seems annoying...what should i be doing here?