The CISCO QSFP-40G-LR4-S is a QSFP transceiver module that provides high-performance 40GBASE-LR4 connectivity for distances up to 10 kilometers over single-mode fiber (SMF). This module is equipped with duplex LC connectors and operates on four wavelengths in the 1310 nm range, using coarse wavelength division multiplexing (CWDM) technology. It is designed for long-range communication, making it an excellent choice for campus, data center interconnects, and metropolitan area network (MAN) applications. The QSFP-40G-LR4-S offers a reliable and efficient way to increase network capacity and extend the reach of high-speed data transmissions without the need for significant infrastructure investments.