Backward not-very compatible that is.
I put my 6141 on S-video or composite output to a NTSC TV, and both left and right sides got chopped to about 10% on each side, making things not fully viewable. Station logos, for example, will be chopped in half.
I tested this on more than 1 set, to make sure that it is not my overscan issue on my CRT, so I also put it on an LCD wide screen monitor but input via S-video and composite. I tried to change settings, but there aren't any inside that I can think of to change.
So sure, if you don't mind things being cut off on the sides, you can say it is "compatible". To me, it is a poor fit. I will take a 2700 over this if watching on an SD set.