48 fiber color code
48-count is the workhorse FTTH distribution cable — four buffer tubes of twelve fibers each. All four tubes follow the TIA-598-C sequence, so if you memorize the order once you can identify any of the 48 fibers on sight.
Tube colors
A 48F loose-tube cable has four tubes — the first four TIA-598-C positions:
- 1. Blue
- 2. Orange
- 3. Green
- 4. Brown
Fiber colors within each tube
Every tube carries the full 12-color sequence. Fibers 1–12 live in the Blue tube, 13–24 in Orange, 25–36 in Green, and 37–48 in Brown.
- 1. Blue
- 2. Orange
- 3. Green
- 4. Brown
- 5. Slate
- 6. White
- 7. Red
- 8. Black
- 9. Yellow
- 10. Violet
- 11. Rose
- 12. Aqua
Complete 1→48 lookup table
| Fiber # | Tube | Tube color | Fiber color |
|---|---|---|---|
| 1 | 1 | Blue | Blue |
| 2 | 1 | Blue | Orange |
| 3 | 1 | Blue | Green |
| 4 | 1 | Blue | Brown |
| 5 | 1 | Blue | Slate |
| 6 | 1 | Blue | White |
| 7 | 1 | Blue | Red |
| 8 | 1 | Blue | Black |
| 9 | 1 | Blue | Yellow |
| 10 | 1 | Blue | Violet |
| 11 | 1 | Blue | Rose |
| 12 | 1 | Blue | Aqua |
| 13 | 2 | Orange | Blue |
| 14 | 2 | Orange | Orange |
| 15 | 2 | Orange | Green |
| 16 | 2 | Orange | Brown |
| 17 | 2 | Orange | Slate |
| 18 | 2 | Orange | White |
| 19 | 2 | Orange | Red |
| 20 | 2 | Orange | Black |
| 21 | 2 | Orange | Yellow |
| 22 | 2 | Orange | Violet |
| 23 | 2 | Orange | Rose |
| 24 | 2 | Orange | Aqua |
| 25 | 3 | Green | Blue |
| 26 | 3 | Green | Orange |
| 27 | 3 | Green | Green |
| 28 | 3 | Green | Brown |
| 29 | 3 | Green | Slate |
| 30 | 3 | Green | White |
| 31 | 3 | Green | Red |
| 32 | 3 | Green | Black |
| 33 | 3 | Green | Yellow |
| 34 | 3 | Green | Violet |
| 35 | 3 | Green | Rose |
| 36 | 3 | Green | Aqua |
| 37 | 4 | Brown | Blue |
| 38 | 4 | Brown | Orange |
| 39 | 4 | Brown | Green |
| 40 | 4 | Brown | Brown |
| 41 | 4 | Brown | Slate |
| 42 | 4 | Brown | White |
| 43 | 4 | Brown | Red |
| 44 | 4 | Brown | Black |
| 45 | 4 | Brown | Yellow |
| 46 | 4 | Brown | Violet |
| 47 | 4 | Brown | Rose |
| 48 | 4 | Brown | Aqua |
Why 48F dominates FTTH
48 strands hits a sweet spot: enough fibers for a neighborhood drop (16 homes × 3 drops = 48, or 24 homes on a 1:2 split), while the cable diameter stays small enough to pull through existing conduit without re-trenching. Crews working brownfield builds see 48F more than any other count.
Field tips
- Mid-span on the Brown tube: easy to confuse with Orange when the jacket is dirty. Wipe the tube with IPA before calling it.
- Loss-budget per fiber: check the OTDR by tube, not by fiber — tube-level loss anomalies usually mean a bend in the buffer, not an issue with any single fiber.
- Splice sheet order: always document in fiber order (1–48), not tube order, to match the central-office terminal block numbering.