Digital studio · declared evidence
ADAT or S/PDIF? Check the optical path.
ADAT and optical S/PDIF can share a TOSLINK plug, but they are different digital formats. ADAT carries up to eight channels at 44.1/48 kHz; S/PDIF carries two-channel PCM. Check the active port modes before buying another cable.
Your declared setup
Only says “OPTICAL”? Find the format first.
A TOSLINK-shaped socket, red light or cable label does not identify ADAT versus S/PDIF. Check the exact device manual and the port’s current control-panel mode.
- ADAT / Lightpipe
- Up to eight channels per link at 44.1/48 kHz. At 88.2/96 kHz, documented S/MUX support reduces this to four per link. Use the ADAT channel and port planner for a channel budget.
- Optical S/PDIF
- Two-channel PCM, not eight separate studio inputs. Encoded surround is a different case; this checker does not verify TV codecs or decoding.
- Find the manual’s digital I/O or optical-port section. A box having eight analogue inputs does not prove that its optical port is ADAT.
- For a switchable port, read the active ADAT or S/PDIF setting at both ends. Connect source OUT to receiver IN.
- If the exact format or mode is still unverified, choose Unknown / only says optical below. Do not infer the format from a working cable or green lock indicator.
Matching formats still need supported sample rates and a clock route. A passive optical adapter does not translate formats. Format source · S/MUX source
A TOSLINK cable is not a format converter
The optical connector can be used for ADAT or S/PDIF. A preamp sending ADAT into an input selected for S/PDIF is not a stereo connection just because both ports take the same plug. Match the declared digital format and OUT-to-IN direction before changing the cable.
Example: ADAT OUT → optical S/PDIF IN with a direct cable flags a format conflict. If the destination manual documents a selectable ADAT input, select that mode in the equipment and enter ADAT here. Otherwise a genuine supported format-conversion device is a different purchase from a passive adapter.
What a matching result leaves open
Matching formats do not establish the number of exposed channels, high-rate S/MUX support, clock lock, signal routing or S/PDIF codec decoding. This checker is for a digital studio path, not a TV-surround/DAC selector. A passive coupler may add optical loss, and a converter may impose its own sample-rate, mapping or clock constraints. Read exact manuals; no universal cable-length or converter compatibility claim is made.
Primary context: Focusrite digital I/O formats. Continue with channel capacity or timing only when that is the missing layer.