Cisco 40GBASE-CSR QSFP Module for Duplex MMFCisco QSFP 40G CSR S: Duplex MMF 40GBASE QSFP+ Transceiver The Cisco QSFP 40G CSR S (S Class) is a high density, pluggable optical transceiver engineered for reliable 40 Gigabit Ethernet links over multimode fiber. This QSFP+ module features a duplex LC connector interface and is optimized for laser graded OM3 and OM4 multi mode fiber, delivering robust performance in modern data centers. With support for demanding uplink and inter switch connections,