# FS.com QDD-2FR4 False Comparable Fix

Date: 2026-05-09
Actor: Codex

## Operator Finding

The dashboard showed invalid comparable products for FS.com `QDD-2FR4-800G`:

- Flexoptix `DQ.2A858HG.z`
  - actually `800G QSFP-DD to 2x QSFP112 Breakout AOC`
  - MMF
  - 1-30m
  - not a 2km SMF FR4 transceiver
- NADDOD `QDD-800LPO-2DR4`
  - 500m
  - not 2km

The operator was correct: these are not 1:1 equivalents.

## Root Cause

FS.com `QDD-2FR4-800G` had:

- `reach_label=2km`
- `reach_meters=0`

The API comparable SQL treated unknown reach as a wildcard, so products with the same form factor and speed could leak into the comparison section even when reach/fiber/protocol differed.

## Live DB Correction

Corrected `FS.COM QDD-2FR4-800G`:

- `form_factor=QSFP-DD`
- `speed=800G`
- `speed_gbps=800`
- `reach_label=2km`
- `reach_meters=2000`
- `fiber_type=SMF`
- `wavelengths=1310`
- `standard_name=800G QSFP-DD 2FR4`
- fully verified remains true

## API Correction

Updated `packages/api/src/routes/transceivers.ts`.

Comparable products now require:

- form factor exact, except `QSFP-DD` and `QSFP-DD800` are treated as one 800G family
- same `speed_gbps`
- known reach on both sides
- reach ratio at least `0.85`
- known fiber on both sides
- same fiber type
- primary wavelength on both sides
- wavelength difference no more than `15nm`
- breakout/AOC/DAC/cable products only compare to breakout/AOC/DAC/cable products

This prevents unknown reach from acting as a wildcard.

## Deployment

On Erik:

- copied API route
- `pnpm -C packages/api build` passed
- `pm2 restart tip-api` completed
- public health after restart: healthy, load ok, memory about 13%

## Lesson For TIPLLM

Never accept dashboard/API comparable output as source truth if any core field is unknown.

For final product comparisons, missing reach, fiber or wavelength evidence must exclude a candidate unless a dedicated reviewed equivalence exists. Breakout/AOC/DAC/cable products must not compare to pluggable optical transceivers unless both sides are explicitly the same breakout/cable class.
