Optical Digital Audio Cable Connection Explained

Choose the link around what you want to hear

If you're looking at both optical and HDMI sockets, we'd check your audio-format needs before choosing a cable. Optical is a useful choice for stereo and basic surround sound, while HDMI supports additional formats that optical can't carry. That distinction matters more to this decision than the fact that both connections send digital audio.

Next, check that both devices have the required optical connection. Availability depends on brand and model, and the two ends have different jobs: the TV sends audio out, while the external audio device receives it. The Samsung worked example below follows that output-to-input path.

Optical, TOSLINK and S/PDIF mean different things

TOSLINK is another name you'll encounter for a digital optical connection. It stands for Toshiba Link, and a device that supports TOSLINK supports digital optical cables. You aren't choosing between two different audio systems when one description says optical and another says TOSLINK.

S/PDIF describes the digital audio interface behind the connection. It can carry audio over a coaxial cable with RCA connector ends or over an optical cable with TOSLINK connector ends. Those are two physical ways of carrying digital audio, so the S/PDIF name alone doesn't tell you which cable connection a device uses.

For this TV connection, identify the optical output and optical input specifically. SVS's explanation of S/PDIF and TOSLINK (opens in a new tab) distinguishes the interface from the cable and connector, which helps when your equipment uses different terminology.

How light becomes sound at the other end

At the sending end, digitally encoded electrical audio signals become light signals. An LED sends those signals through the cable to the receiving device. Inside an optical cable, light travels through fiber strands, typically made from glass or plastic.

The receiving device converts the light pulses back into electrical pulses. Its audio circuitry handles the necessary decoding or processing, conversion to analog and amplification so you can hear the result through speakers. A compatible receiver or powered speaker therefore does work that the cable itself doesn't do.

That separates the connection into useful checks: your TV supplies the digital output, the optical link carries it, and the compatible destination turns that information into audible sound. Connector support and the destination's audio capabilities both matter to the complete path.

The light carries audio only. If your arrangement also needs a video connection, provide that separately. An optical cable between a TV and an audio device handles the sound portion of the setup; it doesn't carry the picture along with it.

The format name decides whether optical fits

Match the full format name to the connection you're considering. PCM 2.0 and multichannel PCM have different optical requirements, as do Dolby Digital and Dolby Digital Plus. Similar names can conceal the exact boundary that determines whether optical suits your listening plans.

The following are interface-level capabilities from SVS's optical format guide (opens in a new tab). Use your products' operating instructions for their own supported settings and connections.

The limit comes from bandwidth: optical connections don't have the capacity for the complete range of audio and surround formats. A stereo format can still be uncompressed, as PCM 2.0 is, so optical's limits aren't accurately described as every signal being compressed or every surround format being excluded.

Will HDMI sound better?

Samsung says optical and HDMI have no difference in sound and send the same sound. Its optical-versus-HDMI guidance (opens in a new tab) also identifies supported formats as the main difference, describing optical support for 5.1 Dolby Digital and DTS and broader format support over HDMI.

SVS gives a more qualified sound-quality comparison: you may hear a difference between lossy surround formats carried over optical and higher-bandwidth lossless formats carried over HDMI. That qualification matters when the connection choice also changes the format you're listening to.

We'd use the format distinction to make this choice, because Samsung's broad sound-equivalence statement and SVS's qualified comparison point to different expectations. Optical remains a useful stereo and basic-surround option; choose an HDMI connection when the format you want falls outside optical's capabilities.

Samsung worked example connecting the cable

This worked example follows Samsung's Singapore support guidance, updated August 3, 2022. Samsung presents it as a common connection method. For model-specific connections and other system settings, follow the operating instructions supplied with your products.

Begin with the cable connection in Samsung's Singapore optical setup instructions (opens in a new tab): insert one end of the digital optical audio cable into the TV's DIGITAL AUDIO OUT port. Insert the other end into the external speaker's DIGITAL AUDIO IN port.

Select the optical output on your Samsung TV

With the physical link connected, move to the TV remote. Samsung's common procedure selects the external optical output through the Sound menu. The menu names below are English samples; Samsung also provides menus in the language of your country.

1. Press Home on the TV remote, then select Settings to open the settings menu.
2. Open Sound, then select Sound Output so you're viewing the output choices.
3. Select Audio Out/Optical as the TV's sound output.

If your TV needs different system settings, use its supplied operating instructions for the model-specific path. Samsung's common optical setup guidance (opens in a new tab) makes that distinction, so follow your product's instructions for settings beyond this shared procedure.