Where selection starts
Define polarity as a verifiable port map, not just a letter option. Fix the viewing direction at both ends and trace channels through trunks, modules and patch cords.
- Decision to make
- After changing a trunk, module or patch cord, review the full map. A component label does not replace an end-to-end check.
- Record to prepare
- Port drawing with key orientation, guide pins and viewing direction, plus channel-by-channel records.
Topic-specific checks
- Draw the complete transmit-to-receive channel map, recording every trunk, module and patch cord; do not record only A/B/C.
- Specify the viewing direction, key orientation and guide pins, and require sample continuity records to match the final port map channel by channel.
Four-step selection check
- Define the actual interfaces and mating parts at both ends
- Record fiber type, count, channel map and polarity
- Confirm length, bend routing, breakout, jacket and environment
- Agree samples, test method, limits and data format
Evidence to request when sourcing
Request drawings, material boundaries, test methods, sample records and batch traceability that match the purchased revision. Certification marks, performance values and environmental ratings matter only when they map to a specific product revision.
This guide is a selection framework, not a substitute for equipment specifications, applicable standards or the approved project drawing.