3CSFP91ST Compatible LC Multi Mode Transceiver Module, Full Duplex. The 3CSFP91ST is an HP 3CSFP91 compatible fiber transceiver module that has been designed, programmed and tested to work with HP® brand switches and routers. It delivers dependable 1 GbE connectivity over fiber cable, for 1000BASE-SX compliant networks, with a maximum distance of up to 550 m (1804 ft).