720 p/1080 p combatibility.....

If you are talking in the context of feeding a Blu Ray Player's signal into an older TV , the 1080p is probably not a supported mode. You should set the Blu Ray output to 720p , the sets native resolution or set the blue ray to 1080I and compare. Not to worry , Im sure either setting will look very good.

You wont have any problems as noted just establish resolution or it may even be automatic.

Prior to the 1080P formats arrival, 720P was the deal... prior to that was the 1080i resolution and aspect ratio.

720p & 1080p are 16 x 9 ratios.

1080i is 4 x 3.

720p & 1080i are currently being transmitted and received via Sat & cable service providers on some channels. 1080P currently only comes from Blue Ray discs.

1080i sets for the most part could do 720p but with the black lines on the screen as that resoltuion would usually not fully fill out the screen... as many were standard type screens or 4:3.

I should think you could set the output of your player to match the TV screen or just choose letter box or pan & scan, try both to see what's best for you and your situation.

Like as not though, if there is no mention of it in your manual... it ain't happening.

1080i is 16:9

Doesn't DISH TV have 1080P?