Connecting a Device with an Optical IN Connector
You can use the projection TV's DIGITAL AUDIO OPTICAL
OUTPUT jack to connect an audio device that is Dolby Digital and
PCM compatible, such as an audio amplifier.
Using an optical cable, connect the device's DIGITAL AUDIO IN
jack to the projection TV's DIGITAL AUDIO OPTICAL OUTPUT
The optical output works only for DTV programming, so you might also want to
connect the projection TV's analog audio out connectors to the amplifier's
analog audio in connectors, as described on page 25.
Setting Up the Projection TV