The Cisco WSP-Q40GLR4L QSFP Module supports link lengths of up to 2 km over a standard pair of G.652 single-mode fiber (SMF) with duplex LC connectors. The 40 Gigabit Ethernet signal is carried over four wavelengths. Multiplexing and demultiplexing of the four wavelengths are managed within the device. It is interoperable with 40GBase-LR4 for distances up to 2km. The operating temperature range is from +10 to +60°C with an optical link budget of 4dB. This 4dB link budget offers the ability to support the loss from patch panels in the link in a data center environment.