Between the transceiver and the structured plant sits the patch cable: a short duplex jumper, almost always terminated in LC connectors, that connects a port to a patch panel or directly to its partner port. GRT’s jumper family is documented in the combinations real plants use — LC-LC for port-to-port and port-to-panel runs, LC-FC where legacy FC panels persist, in single-mode (SM) and multimode (MM) disciplines and in 10G and gigabit grades.
The discipline rules are unforgiving and worth restating: single-mode jumpers (yellow, by convention) never patch a multimode link; a duplex pair must not be split across two different cords; and the A/B polarity of a duplex pair must survive every patch — most "dead link after a tidy-up" tickets are polarity, not hardware. Stocking one jumper family per discipline, labelled by length, prevents all three failure modes.
Documented jumper combinations
- LC-LC multimode duplex — 10G and gigabit grades
- LC-FC multimode duplex — 10G grade
- LC-LC single-mode duplex — 10G and gigabit grades
- MPO-MPO multimode — 8-core and 12-core, 40G class
Why LC-FC?
Many installed panels are FC-terminated. LC-FC jumpers bridge a modern LC device port to a legacy FC panel without an adapter chain.
How should jumpers be stocked?
By discipline and length, in labelled bins, with a spares ratio per length. We can build the schedule from your port map.