26 METHODS OF COMMUNICATION FOR FOREST PROTECTION 



main headquarters, however, is extremely important from every point of view, and 

 i$ should not be decided upon except after very careful consideration of all factors. 



The same is true of the selection of the district headquarters, District boundaries 

 will usually be established on topographic lines; in a mountain or hill country generally 

 along ridge tops, in a flat country along large rivers 1 or lakes. The selection of main 

 and district boundaries and headquarters 1 must be completed as a fundamental pre- 

 liminary before beginning the planning of the system of communication. 



The main principle to be observed in planning an internal system is to have the 

 lines radiate from the main headquarters by the most direct route to each district 

 headquarters. The district headquarters are then used as centrals from which lines 

 radiate to lookout stations and other important points in the district. 



This plan has two important advantages. In the first place each of the several 

 independent circuits from the main headquarters to the districts will be much shorter 

 than single circuits connecting several district headquarters on one line. It is always 

 desirable for the purpose of ensuring the maximum operating efficiency to keep circuits 

 to the minimum length. 



In the second place a break on any of the main lines under this system will isolate 

 only one district, while under a system of through lines joining a number of districts 

 all or several might be isolated by a single break. 



Section 27 Connections to Lookout Stations 



It is important to note also 'that lookout stations should have direct connection 

 with the main headquarters as "well as with the district ranger. This makes it unde- 

 sirable to introduce .a switch between the main line and the lookout station when the 

 line from the lookout station joins the main line at a district headquarters. Isolation 

 of lookout stations must be carefully guarded against, and switches are too likely to be 

 carelessly left open to be tolerated on such lines. 



Other important points to consider in planning a telephone system are the location 

 of test stations, of relay calling stations on extra long lines, and the provision of 

 alternate routes. 



Section 28 Test Stations 



Test stations are points at which, by means of suitable switches, the line may be 

 broken into sections. Ordinarily they are used for the purpose of determining the 

 location of line troubles within definite limits, but they may be very advantageously 

 used for the relaying of calls over a long or a poorly insulated line. For this purpose 

 it is desirable that they be located at stations where switching service can be relied 

 upon. 



Section 29 Relay Stations. 



Relay stations are points on very long lines where it is necessary to repeat long 

 distance calls. With the equipment used on forest telephone lines it is nearly always 

 possible to talk much farther than it is possible to signal with the call bells. Circuits 

 must not be planned to operate regularly on this basis, however, but in very large 

 contiguous areas conditions sometimes occur which make it desirable to consider the 

 possibilities for relaying calls. Under such conditions relay stations may be employed 

 and they must be located at points where continuous switching service is available. 



Section 30 Alternative Routes 



Alternative routes are secured by building connecting lines across the relatively 

 short gaps that sometimes occur between the ends of separate branches. They make it 

 possible to reach each station on both lines from two different directions and, therefore, 

 greatly reduce the chance of any one station being cut off from communication. Since 



