Optical audio sends a digital S/PDIF stream as pulses of visible red light through a plastic fiber, terminated in the JIS F05 plug the market calls TOSLINK. Toshiba's module family is specified at a 650 nm typical wavelength and DC to 10 Mb/s data rate, fast enough for the consumer digital audio interface IEC 60958-3 defines. TVs label the output formats PCM, Dolby Digital, Auto or Pass-through, and Samsung notes optical cables cannot carry modes beyond 5.1 channels. A receiver with an optical output hands the same stream to a DAC or AVR.
Figures on this page were checked October 2026. Every table row carries its source and access date.
Optical audio: the link in one view
Optical audio is the consumer digital interface delivered over plastic fiber: the source encodes the S/PDIF stream, an LED turns the bits into flashes of visible red light, and a photodiode at the far end rebuilds the electrical signal. Toshiba supplies matched module pairs for exactly this job and catalogs them as TOSLINK general-purpose optical transmitting and receiving modules, which is where the connector's market name comes from.
Because the bridge between the two boxes is light, the link carries no ground reference across, which is the property installers reach for when two mains-powered boxes refuse to stay quiet together. The fiber is all-plastic, and Toshiba specifies it at 980 um core inside 1000 um cladding.
Physical layer data (Toshiba TOTX1350(F))
| Field | Value | Source / as of |
|---|---|---|
| Connector | JIS F05 type fiber optic connector | Toshiba TOTX1350(F) datasheet, 2026-10-13 |
| Light source / wavelength | 650 nm LED, center emission 650 nm typ | Toshiba TOTX1350(F) datasheet, 2026-10-13 |
| Data rate | DC to 10 Mb/s (NRZ) | Toshiba TOTX1350(F) datasheet, 2026-10-13 |
| Fiber | All plastic fiber, 980 um core / 1000 um cladding, NA 0.5, loss under 0.18 dB/m | Toshiba TOTX1350(F) datasheet, 2026-10-13 |
| Transmission distance, component link | 40 to 100 m with the matched receiver at 6 mA drive | Toshiba TOTX1350(F) datasheet, 2026-10-13 |
| Operating temperature | -40 to +85 C | Toshiba TOTX1350(F) datasheet, 2026-10-13 |
| Product family / status | TOSLINK general-purpose optical transmitting modules; Not Recommended for New Design (this part number) | Toshiba product page, 2026-10-13 |
Two layers of distance live in that table and they are not the same claim: the 40 to 100 m row is a component-level link specification with a matched receiver and drive circuit, not a promise about the patch cable in a TV cabinet. Consumer cables are bought pre-terminated in fixed lengths and no consumer length rule is published on the pages this reference draws from.
Standards lineage
| Name | What it is | Source / as of |
|---|---|---|
| S/PDIF | The Sony/Philips Digital Interface, the consumer digital audio format carried over optical fiber or coaxial cable | Common name; format standardized in IEC 60958-3, 2026-10-13 |
| IEC 60958-3:2021 | "Digital audio interface - Part 3: Consumer applications", edition 4.0, published 2021-09-02 | IEC catalog, 2026-10-13 |
| JEITA CPR-1205 | Japanese consumer digital interface standard, successor of EIAJ CP-1201 and CP-340, listed alongside IEC 60958 on current interface chips | TI DIR9001 compliance list, 2026-10-13 |
Current silicon closes the loop between the documents and the port: TI's DIR9001 receiver documents compliance with IEC 60958 and JEITA CPR-1205, with a 96 kHz / 24-bit capability and a 28 to 108 kHz biphase input range, and the optical modules above are specified at 10 Mb/s, bandwidth to spare for either format tier.
What the source sends: formats and the 5.1 ceiling
The fiber does not choose a format; the source's menu does. Samsung's TV guide names the options on the Digital Output Audio Format setting: PCM for plain stereo, Dolby Digital for compressed surround "suitable for optical cables", Auto to follow the content, and Pass-through for handing the stream to a soundbar. One line of that guide settles the ceiling question in Samsung's words: "Optical cables cannot support modes beyond 5.1 channels; use HDMI ARC for these setups." The same logic runs on the coaxial variant of the interface, which carries the S/PDIF format over copper with an RCA-type plug instead of light, a topic our RCA connector reference treats from the plug side.
Going wireless into an optical input
Plenty of good DACs, AVRs and soundbars take optical only, and the wireless path into them is a receiver that outputs S/PDIF rather than analog. On the receiving side of the Bluetooth link the codec negotiation happens exactly as our Bluetooth 6.0 data page describes; on the output side the receiver hands the decoded stream to the optical port and the fiber takes over. For TV-side context, the TV audio guide maps the output options on current sets.
FAQ
It is the consumer digital audio interface carried on light. An LED at the send end pulses visible red light down a plastic fiber to a photodiode at the receive end, in the data format IEC 60958-3 specifies for consumer applications. Toshiba, which supplies the transmitting and receiving modules, catalogs the link under its TOSLINK name.
Not exactly. S/PDIF names the consumer digital audio format, and TOSLINK names Toshiba's optical module and plug family that carries it over fiber. The same S/PDIF format also runs over coaxial cable with an RCA-type plug, so TOSLINK is one physical carrier for the format, not the format itself.
Stereo PCM and compressed surround such as Dolby Digital, selected on the source. Samsung's TV guide lists the menu choices as PCM, Dolby Digital, Auto and Pass-through, and states that optical cables cannot support modes beyond 5.1 channels, pointing owners who need more at HDMI ARC. The fiber link itself is fast, but the format table on the source decides what actually travels.
Use a Bluetooth receiver whose output side is digital. The blafili B3 receiver lists optical and coaxial outputs next to its XLR and RCA jacks on the QCC5125 + ES9018K2M platform, so it can feed a DAC or AVR that accepts a toslink input while the wireless link stays on the receiver side.
blafili B3 Bluetooth Receiver
Optical and coax outputs alongside XLR and RCA, with the QCC5125 + ES9018K2M platform for putting a wireless source behind digital inputs.
- Toshiba, TOTX1350(F) datasheet (2020-03-12): "JIS F05 type fiber optic connector", "650 nm LED", center emission wavelength 650 nm typ, data rate DC to 10 Mb/s, all plastic fiber 980 um core / 1000 um cladding NA 0.5 with transmission loss under 0.18 dB/m, transmission distance 40 to 100 m with TORX1350A(F) at 6 mA drive, operating temperature -40 to 85 C. Hosted by Mouser: mouser.com/datasheet/2/408/TOTX1350(F)_datasheet_en_20200312-1760543.pdf, accessed 2026-10-13
- Toshiba, TOTX1350(F) product page: "TOSLINK General-Purpose Optical Transmitting Modules", data rate DC to 10 Mb/s, dominant emitting wavelength 650 nm typ, max transmission distance 100 m, supply 4.75 to 5.25 V, status Not Recommended for New Design. toshiba.semicon-storage.com/us/semiconductor/product/isolators-solid-state-relays/detail.TOTX1350(F).html, accessed 2026-10-13
- Texas Instruments, DIR9001 product page: "Compliant With Digital Audio Interface Standards: IEC60958 (former IEC958), JEITA CPR-1205 (former EIAJ CP-1201, CP-340), AES3, EBU tech3250"; 96-kHz, 24-bit digital audio interface receiver, biphase input sampling range 28 kHz to 108 kHz. ti.com/product/DIR9001, accessed 2026-10-13
- IEC, IEC 60958-3:2021, "Digital audio interface - Part 3: Consumer applications": specifies the consumer application of the interface for interconnection of digital audio equipment; edition 4.0, published 2021-09-02. webstore.iec.ch/en/publication/62827, accessed 2026-10-13
- Samsung, "Change the audio format on your Samsung TV": Digital Output Audio Format under Settings, All Settings, Sound, Expert Settings; PCM outputs left and right only; Dolby Digital "offers up to 5.1 channels of compressed audio, suitable for optical cables"; Pass-through for soundbars; "Optical cables cannot support modes beyond 5.1 channels; use HDMI ARC for these setups." samsung.com/us/support/answer/ANS10005199, accessed 2026-10-13