(Coarse Wavelength Division Multiplexing) A method of transmitting several connections parallel over one fiber optic line. Transmission works over different wavelengths (colors) on the same fiber, which do not influence each other. As opposed to [DWDM], a relatively wide channel spacing is used, which leads to a more cost-saving technology, because temperature stabilized components are not needed. CWDM has been specified for use on distances up to 50 km. The CWDM wavelength plan of the ITU-T Recommendation G.694.2 defines 18 wavelengths with a grid of 20 nm. But two of these are located in the area of the [Water Peak] and therefore are being omitted. Because of this, CWDM provides 16 usable parallel data channels.