The QSFP28 transceiver is a quad small form-factor pluggable module delivering 100GBASE-BX connectivity over single-mode fibre (SMF) with a transmission reach of up to 80 km. It operates on 1270 nm (TX) / 1310 nm (RX) wavelengths and uses a standard LC connector. The module integrates cooled 4 × 25. This guide provides the definitive roadmap for selecting, deploying, and troubleshooting QSFP28 transceivers while bypassing the painful trial-and-error phase. It is widely used in data centers, enterprise core networks, and telecom infrastructure due to its high port density, standardized interface. The QSFP28 (Quad Small Form-factor Pluggable 28) transceiver is a compact module that can be hot-swapped and is designed to support high-speed data transfer in today's network. Please refer to the respective datashee min Tx power and Rx sensitivity. Dispersion/path penalties not taken into account. FEC: If FEC is required in host quipment for performance @ 1 GHz grid and with integrated FEC. Requires a DCP Open min Tx power and Rx. Amphenol's 100G QSFP28 optical modules include SR4, AOC, AOC break out, CWDM4, LR4, ER4 Lite, ER4 and ZR4 series, which adopt LC or MPO optical ports and are compatible with IEEE802.