Audio Digital Optical Out, commonly labeled as Optical Out or TOSLINK, refers to a specific physical port and corresponding cable standard designed to transmit digital audio signals between devices using pulses of light.
What It Is & How It Works
An Optical Out port utilizes a standardized TOSLINK connector. The cable houses a thin optical fiber core. Audio data is transmitted digitally as rapid flashes of light generated by an LED within the transmitting device.
The signal conforms to the S/PDIF (Sony/Philips Digital Interface Format) protocol, carrying uncompressed stereo PCM audio or compressed multi-channel audio formats like Dolby Digital or DTS. This transmission method is inherently immune to electromagnetic interference (EMI) and radio frequency interference (RFI), preventing hum or buzz often caused by electrical ground loops.
Common Uses for Optical Audio Out
Digital Optical Out ports are frequently found on these devices:
- Televisions: Sending audio to soundbars, receivers, or home theater systems.
- Blu-ray Players & DVD Players: Transmitting high-quality surround sound tracks.
- Set-Top Boxes & Game Consoles: Providing digital audio output.
- Computers & Laptops: Offering a dedicated digital audio output path.
- CD Players & Digital Media Streamers: Sending pristine stereo PCM audio.
Key Advantages & Limitations
Advantages:
- Eliminates electrical ground loop noise.
- Immune to electromagnetic interference (EMI/RFI).
- Supports common compressed surround formats (Dolby Digital, DTS).
- Simple plug-and-play connection.
Limitations:
- Typically limited to 2 channels (stereo) for uncompressed PCM audio.
- Does not support modern high-bandwidth uncompressed surround formats (e.g., Dolby TrueHD, DTS-HD Master Audio) or object-based formats like Dolby Atmos transmitted as raw PCM data (requires HDMI ARC/eARC).
- Cables can be less durable than copper alternatives if bent too sharply.
