655 is an ITU-T Recommendation that specifies the geometrical, mechanical, and transmission attributes of a non-zero dispersion-shifted single-mode optical fibre and cable, designed to minimize dispersion while supporting high-bit-rate, long-haul transmission. G. This single mode fibre supports high-power signals and longer distances, as well as closely spaced DWDM (dense WDM) channels at rates. t the wavelength range from 1530 nm to 1565 nm. This dispersion reduces the growth of non-linear effects which are particularly deleterious in dense wavelength division multiplexing systems. The last revision in 2006 adds two new categories of this fibre in Tables D and E. First published in 1996.