Connections & formats
Optical (TOSLINK)
Also called TOSLINK, optical cable, optical S/PDIF
TOSLINK is the optical version of the S/PDIF digital audio connection: a plastic fiber carrying the signal as pulses of red light. It is found on televisions, game consoles, CD players and most DACs, and it is immune to electrical hum and ground loops.
Because light cannot carry a ground, an optical link breaks any electrical connection between source and DAC, which is the simplest fix for a hum caused by a ground loop. Toshiba introduced it in the 1980s, hence the name.
The limits are bandwidth and the cable. Most optical inputs top out at 24-bit/96 kHz, sometimes 192 kHz, and rarely carry DSD: only DSD64 packed as DoP, and only where both ends support 176.4 kHz. The plastic fiber should not be bent sharply, and the source’s clock sets the timing, so Jitter depends on the transmitter more than with USB. The electrical twin is coaxial S/PDIF, which carries the same data on a wire.
Where you’ll see this on tonistry.
- Optical/TOSLINK is one of the connection types members pick when they draw a signal chain.