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 shall satisfy in order to be categorized as meeting the IEC standard category C-controlled environments. The requirements cover devices with single-mode non-connectorized pigtails and no circuit-board. There is also a distinction between small-scale (N < 16) and large-scale (N > 64) 1 N DWDM devices for the purpose of standards.