When a duplex link shows light leaving both transceivers but neither receives, the pair is crossed the wrong way, and the quick fix is to reverse the two connectors at one end. Many LC duplex clips can be opened and flipped for exactly this. Crews say roll it, flip it or swap the pair, and the change should be made at a jumper, never by re-terminating the permanent cable.
Still no link on 24, roll the pair at the patch panel and tell me what the switch says.
Also heard as
- flip
- swap the pair
- roll the fibers
Related terms
Polarity
The arrangement that ensures each transmitter in a fiber link connects to the receiver at the far end.
Jumper
A short fiber cable with connectors on both ends, used to patch equipment to panels or panels to each other.
Zipcord
Duplex fiber cable made of two simplex cords joined side by side, like lamp cord, used mainly for patch cords.
Light levels
The transmit and receive optical power readings on a transceiver, read from a meter or the switch's optic diagnostics.