In this paper, 4 NRZ modulated signals at 2.5Gb/s rates, transmitted over a medium haul link with 1nm spacing.The signals are preamplified by an EDFA booster and transmitted over a sequence of 2dispersion shifted fiber spans of 100km each. The fiber has opposite dispersion signs resulting in ideal dispersion compensation at the middle of the bandwidth. Further, results are observed with 8, 16 and 32 channels WDM with different length of fiber and graphical result obtained for respected channels.