138 



METHO'DS OF COMMUNICATION FOR FOREST PROTECTION 



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Fig. 8-8 Telephones connected in series on a metallic line 



A/a//? /me 



Protector 



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Fig. 89 Telephones connected in series on a grounded line 



2 BRIDGING-BELL SYSTEM 



For the purpose of overcoming the difficulties inherent in the series system the 

 bridging or multiple method of connection was adopted and is now the standard 

 method of connecting up party lines isuch as are employed in forest protection. All 

 the standard instruments of the Forestry Branch are wired for this system only, and 

 all lines installed are of the bridged type either grounded or metallic. The method of 

 connecting the telephones to the line by this system is shown in Figs. 90 and 91, the 



