IEC 61753-081-2:2014 contains the minimum initial test and measurement requirements and severities which a fibre optic middle-scale 1 x N (16 ≤N ≤64) DWDM (dense wavelength division multiplexing) device with channel spacing of 50 GHz, 100 GHz or 200 GHz needs to satisfy in order to be categorized as meeting the requirements of category C - Controlled environment. The requirements are given for the DWDM devices with Gaussian passband profile and flat-top passband profile. The requirements cover devices with single-mode non-connectorized pigtails and no circuit board. This second edition cancels and replaces the first edition published in 2009 and constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: - to add passband ripple as a test item; - to revise details to be specified and the formats of Tables 2, 3 and 4; - to add IEC 61300-3-38 as a normative reference. Key words: fibre optic middle-scale 1 x N (16 ≤N ≤64) DWDM (dense wavelength division multiplexing) device, channel spacing of 50 GHz, 100 GHz or 200 GHz, category C - Controlled environment.