18 Jul 2026

Setting the Optocore loop: two consoles, three racks

One closed Optocore ring linking FOH and monitor world — FOH console and rack on one side, MON console with two racks on the other. Five devices, one loop, red carrying the send, blue carrying the return.

The shape of it

Five devices, one ring — no dual-loop trickery, since two independent loops is an SD5/SD7-only feature and nothing here needs it. One loop, one ID scheme, one fibre speed for the whole system, all five devices on the same ring regardless of which side of the stage they sit on.

RED — Snd, outbound, clockwise BLUE — Rcv, return, counter-clockwise

Red to A, blue to B? DiGiCo's ports genuinely are labelled A and B — pick A as red and B as blue and hold that on every device, no exceptions. That consistency is the entire value of the scheme: a fresh pair of eyes at 2am on a fibre run doesn't have to trace the cable, just check colour against letter.

But don't assume A pairs straight across to A at the far end. DiGiCo has one documented case where it doesn't — wiring an R-series Optocore box (DD4MR, X6R, etc.) into an SD console's loop ports crosses: DiGiCo A → Optocore Link 2, DiGiCo B → Optocore Link 1, not 1-to-1. That rule is written for R-series boxes specifically; there's no confirmation it applies between two plain SD Racks/consoles in a ring like this one. Treat "A is always red" as solid — treat "A always lands on A at the other end" as something to verify at the connector.

Step by step

Do these in order — ID and fibre-speed decisions upstream save you from chasing a "loop won't link" fault later, especially with five devices instead of two.

Plan the ring and write down every ID

Five devices, five unique Optocore IDs. Consoles take the low primary IDs; racks take the rack range — and with two racks sharing monitor world, they still each need their own unique number.

FOH Console → ID 1 · MON Console → ID 3 · FOH Rack → ID 11 · MON SD-Rack → ID 12 · MON SD-Mini Rack → ID 13

Neither console is a dual-loop SD5/SD7, so there's no loop-1/loop-2 split to think about — every device lives on the one loop, primary console IDs run odd (1, 3, 5, 7, 9).

Run the physical ring — and colour it

Thread one continuous fibre path through all five devices and back to where it started:

FOH Console → FOH Rack → [run to stage] → MON SD-Rack → MON SD-Mini Rack → MON Console → [run back] → FOH Console

Five hops, five unique IDs, one loop. Every hop's send-direction fibre is red, its return-direction fibre is blue — same physical port position on every device. Never cross a red into a blue port.

Set each rack's ID and fibre speed

On each rack's MADIPod display: unlock with left + right held 2 seconds, set Rack Type to match the physical unit, then open Optocore ID & Fibre Speed and dial in the ID. Do this on all three racks — easy to do two and forget the small one.

Fibre speed must match on all five devices. Default is 2G — only drop to 1G for a run over ~350m or 1G-only gear. Dropping to 1G caps the whole system at 224 I/O @ 96kHz — don't do it on just one rack, a mismatched device simply won't link.

Enable Optocore on both consoles

Options → Console menu → Enable Optocore on each desk, then restart. Since neither console has dual-loop optics, this is a straight on/off — no Loop 1 / Loop 2 / Both choice to make.

Set the clock source — on both engines

Sync source = Optocore on both consoles. Not Master, not Internal — those are for MADI-only rigs and will hand you random clock errors here for no benefit.

The lowest ID on the ring (FOH Console, ID 1) becomes clock master automatically. If it drops off the loop, ID 3 takes over instantly — no menu diving required mid-show.

Power up, close the loop, bring up I/O

Both PSUs on every rack, both separately earthed. Patch the ring closed across all five devices, power everything, then on each console: Setup Optocore → Conform All Ports, then check the Optocore Details panel — all three racks should show, sample rate correct, no channel errors.

Head into Audio I/O on each console and pull the channels you need — a channel from the small MON SD-Mini Rack routes exactly the same way as one from the main MON SD-Rack, the loop doesn't care which rack it physically came from.

Verify the ring is actually closed

On each rack's main display, confirm s: O (Optocore-synced) and that the sync-order line shows the active arrow under O. All five devices should agree on sample rate.

The real proof: with a channel live, pull one fibre leg — unplug a blue return run at the furthest rack from FOH — and confirm audio holds. The ring should self-heal through the other direction instantly. Reconnect straight after; don't leave a leg open on a show day.

Quick reference

Device	Role	Optocore ID	Fibre speed
FOH Console	—	1	2G
MON Console	SD-Mini	3	2G
FOH Rack	SD Rack	11	2G
MON SD-Rack	SD Rack	12	2G
MON SD-Mini Rack	—	13	2G

Sources: TN320 (SD dual-loop info, primary ID scheme), TN300 (Optocore clock operations), TN319 (Optocore port labelling and the R-series A/B cross gotcha), SD Rack User Manual B (rack menu system, ID range, fibre speed). Model/ID assignment for the MON SD-Mini Rack assumed to follow the same rack-class rules as the full SD Rack — verify against that unit's own manual on site if it differs.