Overview Tripp Lite's 5-meter ( 15ft ), Plenum Rated singlemode duplex fiber optic LC/ST patch cable is manufactured from 8.3/125 zipcord fiber. The cable has LC connectors on one end, ST connectors on the other, and is FDDI and OFNR rated. Duplex singlemode fiber is most commonly used in LAN applications. Plenum cable is used in plenum return air chambers where local fir codes dictate the use of plenum rated cable.