This part of IEC 61753 contains the minimum initial test and measurement requirements and severities which a non-connectorized single-mode fibre optic Local Area Network Wavelength Division Multiplexing (LAN WDM) device with channel spacing of 800 GHz needs to satisfy in order to be categorized as meeting the requirements of Category C – Controlled environments, as defined in Annex A of IEC 61753-1:2007. The applications of LAN WDM devices are optical MUX and DEMUX for 100GBASE-LR4 (required operating range of 2 m to 10 km) and 100GBASE-ER4 (required operating range of 2 m to 30 km) defined in IEEE P802.3ba, as shown in Annex D. The requirements cover both an integrated 1 × 4 LAN WDM device and an individual 1 × 2 LAN WDM device for cascaded module construction.