3Com CoreBuilder 3500 Installation Manual page 9

70-km Gigabit Ethernet GBIC Transceiver Installation Guide
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
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