Easiest way to get an answer is to list what outputs ARE available on the DirecTV set top box and what inputs are available on the HDTV. Common ports include
HDMI (not possible, we get that).
Composite (Yellow video + Red/White audio)
Component (Red, Blue, Green video + Red/White Audio)
VGA (Typically Blue 15-Pin D-Sub)
SVGA (single cable with 7 pins).
-Wolf sends