Hi. I have the same set up. you need an audio reciever with
AC3 inputs. Most home theatre boxes with Dolby Digital have them.
Run a cable with RCA type connectors from the 'S/PDIF' port in the back of the 2500 to the 'Digital in' or 'coaxial in' on the back of whatever audio receiver you are using (that digital in port may be called any of several different things).
Be careful of the
HDTV transponder for
PBS on AMC3. whenever i tune to it, it crashes my pansat and i need to turn off the switch in back.