Fibre strands¶

A fibre cable isn't one wire — it's a bundle of strands, each an independent light path. Danbyte lets you record how many strands a fibre cable carries, colour-code them to the industry standard, and label each one.

How much you model — the modelling setting¶

Not every team wants to track fibres. Customize → Fibre colours has a per-tenant Fibre modelling switch:

• Off — a cable is just a cable; no fibre UI appears anywhere.
• Count + colours (default) — strand count, colours and labels; the trace follows strands straight-through the panels. This is the everyday level.
• Strand-accurate — also model multi-fibre connectors (below); the panel front-port form gains a Fibres field.

Turn it Off and the whole feature gets out of your way.

Multi-fibre connectors (LC-duplex, MPO)¶

A patch-panel rear port has N positions (strands). A front port used to tap exactly one — but a real LC-duplex connector carries 2 fibres and an MPO carries 8–24. With modelling set to Strand-accurate, a front port has a Fibres count and claims that many consecutive rear positions from its start (e.g. an LC-duplex at start 1 owns strands 1–2). Danbyte validates that the range fits the rear port and doesn't overlap another front port. Picking a connector type (LC Duplex, MPO-12 …) pre-fills the count — you can still edit it.

Finding fibre cables¶

DCIM → Fibre cables lists every cable whose type is a fibre medium, with a filter rail — narrow by type (mmf-om4, smf-os2 …), strand count, or status, and search by device/port. Each row shows a colour strip of its first strands; click through to the cable's Fibres section.

Turning a cable into a fibre cable¶

Any cable whose type is an optical-fibre medium (single-mode smf* or multimode mmf*) gets a Fibres section on its detail page (Overview tab).

1. Set the strand count (2, 12, 24, 48, 96…).
2. The strands render as coloured swatches, grouped into rows of 12 (one row per buffer tube / ribbon).
3. Click a strand to give it a label (e.g. "Cust-A pri") and a status (in use · spare · reserved · dark · damaged). Dark/damaged strands render dimmed so they're obvious at a glance.

Only the strands you annotate are stored — an un-labelled 288-fibre trunk costs nothing.

The colour standard (TIA-598-C)¶

Strands follow TIA-598-C, the 12-colour sequence:

Blue · Orange · Green · Brown · Slate · White · Red · Black · Yellow · Violet · Rose · Aqua.

Past 12 the sequence repeats, and each repeat is marked with a diagonal tracer (a contrasting stripe, like a real striped fibre):

• Strands 13–24 — the base colours with one tracer stripe.
• Strands 25–36 — two stripes; 37–48 — three; and so on.

So strand 25 reads as "Blue with two tracers" — the third dozen. The tracer colour is picked to contrast the fill, and White, Black and Aqua get a thin outline, so every strand stays legible in light or dark mode. (Each row of the fibre map is also one 12-fibre unit, labelled by its buffer-tube colour.)

Customising the palette — Fibre colours settings¶

Customize → Fibre colours (/fiber) is a per-tenant setting for the strand colour order. It defaults to TIA-598-C. You can:

• Reorder colours (move up / down),
• Recolour them (colour picker or hex),
• Add / remove entries, or
• Reset to TIA-598-C.

A live 24-strand preview shows the effect. The tracer rule (stripe past 12, ring on each further wrap) always applies on top of whatever colours you choose. Every fibre map in the app — cable pages and (later) the trace views — uses this palette.

Tracing a strand end-to-end¶

On a trunk cable (both ends on patch-panel rear ports), strand k is a real, independent light path: it maps to position k on each rear port, breaks out through the panels' front ports, and patches on to the end devices. Click a strand (or Trace in its editor) to follow it end-to-end through the panels — device-A ═ panel ═ TRUNK (strand k) ═ panel ═ device-B, drawn as a path strip with the trunk segment in the strand's fibre colour. The header shows whether the run is complete (both ends reach a real port) or stops at a dangling panel.

Strand-to-position is 1:1 by construction, so this works on any trunk with no extra setup.

In the path / trace views (the device "Paths" tab, cable trace, and the map deep-view — all the same shared strip) a fibre cable is marked with a small duplex glyph and drawn as a thin duplex rail, and where a run threads a strand-bearing trunk the segment is drawn in that strand's colour with a ● strand N tag. So you can see, at a glance, which fibre a run rides through each panel. A quick Trace button (⟿) sits on every row of the Cables and Fibre cables lists and on each cabled port in a device's Hardware tab — it opens the end-to-end run in a dialog without leaving the page.

How a strand maps to a front port¶

This is the patch-panel model, and you control it — nothing is guessed:

• A panel's rear port has a number of positions (its strand count). Strand k of a trunk cabled onto that rear port is simply rear position k — a fixed 1:1 mapping.
• Each front port taps one rear position via its rear_port_position. Front port f1 with rear_port_position = 1 breaks out strand 1; set it to 7 and that front port now taps strand 7.

So "which fibre goes to which front" is exactly the front port's rear_port_position, which you set when you create or edit the front ports (Device → Hardware → front ports, or on the device type's port templates). The trace then follows that mapping automatically: strand k → rear k → the front port whose position is k → whatever's patched onto it.

Splice closures¶

A splice closure is just a device whose type has front and rear ports mapped 1:1 — a cable in, a cable out, and the trace walks straight through it like any patch panel. Model one as a device type ("Splice closure 48F": one 48-position rear port + 48 front ports, or 48 rear/front pairs for inline splices), create devices from it, and cable through. If a mid-span closure should show up in the site map's cross-site cable bundles, give it its own (small) Site so the bundle splits at the closure.

PON splitters¶

An optical splitter broadcasts one input to every output — a different animal from a panel's 1:1 pass-through, so it gets its own flag: tick Optical splitter (PON) on a rear port (or a rear-port template, so every device from the type is born a splitter). The rules:

• a splitter rear port has exactly 1 position — the input;
• its front ports are the outputs, all mapped to position 1 (the usual one-front-port-per-position rule is lifted);
• tracing fans out: from the OLT you reach every ONT behind the splitter (cascades included); from one ONT you reach the OLT and the sibling ONTs — the shared-medium reality of a PON tree;
• the topology map and cable traces keep the splitter as a visible node (it is never collapsed away like a patch panel), badged as a splitter.

A typical build: device type "1:8 splitter" = one rear port (positions 1, splitter ticked) + front ports out[1-8]. Feeder cable into the rear, drop cables out of the fronts.

Building a PON, end to end¶

Nothing here is pre-filled — you define the vocabulary once, then stamp it out:

1. The OLT is an ordinary device. Give its device type PON interfaces — interface type gpon / xgs-pon / epon… (the PON family is in the interface-type list). Each PON port feeds one splitter tree.
2. The splitter is a device type with one rear port (positions 1, Optical splitter (PON) ticked) and its outputs as front ports — out[1-8] for a 1:8. Create a device from it wherever the splitter lives (street cabinet, basement, closure).
3. The ONTs are devices with a PON-type interface each.
4. Cable it: feeder cable from the OLT's PON interface to the splitter's rear port; one drop cable from each splitter front port to each ONT.
5. Trace: from the OLT port you'll reach every ONT; from any ONT you'll see the OLT and the siblings (a PON is a shared medium). The splitter stays a visible, badged node on the trace and topology views.

Cascades just repeat step 2–4 (splitter front → next splitter's rear).

Geographic routes — fiber on the site map¶

The site map draws every cable whose ends are placed — no route required. Click a device to see its cabling and ports, trace a run on the map, or ＋ Connect an empty port to wire a cable right there. Draw routes (ducts, aerial spans, trenches) in the map's Cables mode when you want a cable to follow real geometry instead of a straight chord; assign cables to a route as you draw it or from the route inspector. Every cable page gets a Show on site map button once it's placed.

What's next¶

Binding a strand to a non-sequential far-end position, duplex/MPO grouping, 2:N splitters, and per-strand splice management — see fibre strands — design.