The QSFP28 module provides 100GBase-LR4 throughput up to 10km over a standard pair of single mode fiber (SMF) with duplex LC connectors. This transceiver is compliant with SFF-8661, SFF-8636,IEEE 802. 3 100GBASE-LR4 and QSFP28 MSA standards. Digital diagnostics functions allow access to real-time. QSFP28 (Quad Small Form-Factor Pluggable 28) is a compact transceiver form factor designed for high-capacity 100G Ethernet. It is widely used in data centers, enterprise core networks, and telecom infrastructure due to its high port density, standardized interface. This article provides a comprehensive comparison of mainstream optical transceivers, including SFP, SFP+, QSFP+, QSFP28, and QSFP-DD. The same 400 modules would have cost $112,000.