3Com 3CB9LF20R Installation Guide - Page 9

70-km Gigabit Ethernet GBIC Transceiver Installation Guide 9 Sample Calculations System A 60 km of fiber with 8 mating connectors: 1 60 km of single-mode fiber x 0.25 dB per km = 15 dB fiber attenuation 2 8 mating connectors x 0.50 dB per connector = 4 dB connector attenuation 3 15 dB fiber attenuation + 4 dB connector attenuation = 19 dB total link attenuation System B 75 km of fiber with 2 mating connectors: 1 75 km of single-mode fiber x 0.25 dB per km = 18.75 dB fiber attenuation 2 2 mating connectors x 0.50 dB per connector = 1 dB connector attenuation 3 18.75 dB fiber attenuation + 1dB connector attenuation = 19.75 dB total link attenuation System C 90 km of fiber with 4 mating connectors: 1 90 km of single-mode fiber x 0.19 dB per km = 17.1 dB fiber attenuation 2 4 mating connectors x 0.5 dB per connector = 2 dB connector attenuation 3 17.1 dB fiber attenuation + 2 dB connector attenuation = 19.1 dB total link attenuation