Optex BTR-5030 User Manual page 12

S.T.B Connection
2. How to connect the Audio system
Connect the AUDIO R/L socket of the STB to the Audio System like HI-FI,
Amplifier, etc.
Audio System must capable of stereo audio ability.
③If Digital Audio or S/PDIF Optical output are available on STB, you can get
better stereo experience.
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