CHAPTER XII 



INSTALLATION OF FIXED EQUIPMENT 



Section 69 Wall Sets 



The standard wall telephone set will always be the most common type employed. 

 It is used for nearly all permanent indoor installations, except at lookouts or main 

 headquarters, where desk sets are desirable. The sets as received from the maker are 

 in a partly "knockdown" condition and must be assembled. This consists of putting in 

 place the receiver, transmitter, shelf, and generator crank. Suitable screws are pro- 

 vided, where needed, and holes bored for them. Directions for assembling accompany 

 each set, as shown in Fig. 41. 



The location of the instrument inside the building will always be determined largely 

 by convenience in using it. This location should be decided upon, however, before the 

 line wire is brought up to the building. It is customary to stand up when using a wall 

 set, and the height of instrument must be determined accordingly. Instruments must 

 not be attached to walls with nails. Use the four If-in. No. 10, round-head, blued screws 

 provided, and make Certain that the screws get a sufficient hold on the wall to support 

 the weight of the set and the extra weight of persons leaning on the shelf. Instru- 

 ments installed in unlined log buildings should be attached to a suitable board and 

 this in turn fastened securely to the wall. Always try to place the instrument so that 

 it will be directly over the point of grounding. 



Each standard instrument when received should have pasted to the inside of the 

 door, a diagram of the internal wiring and complete directions for setting up and 

 connecting to the line (see Fig. 41). It is to be noted that the wires from different 

 parts of the set are variously coloured and these colours are indicated on the simpli- 

 fied diagram, making it easy to identify various circuits in the set itself. 



The two terminals on the right-hand side of the instrument marked Ll and L2 

 are the ones to which the .line wire and ground wire respectively must be connected. 

 [In some older types of instruments on a few reserves these terminals are -on the left 

 side of the box. The diagram, however, will indicate connections.] 



On a metallic circuit connect one of the wires to each of these terminals. The 

 terminal marked GND is not used at all in the set as employed on Forestry Branch 

 lines. 



Section 70 Condensers 



The condenser in a telephone is cut in circuit in series with the receiver. It makes 

 possible "through" signalling when receivers at intermediate stations are off the hooks. 

 Any telephone now in use, if not already provided, can be equipped with a condenser. 



The condenser may also be cut in on one side of the ringers for testing purposes. 



Section 71 Dry Batteries 

 1 INSTALLATION 



Three dry cells are required for all instruments except the lookout sets and the 

 portables. Northern Electric, Blue Bell, Blue Label, or Columbia cells are recom- 

 mended and those with Fahnestock clips are to be preferred to those with the common 

 binding-post. C'onnect together as shown in Fig. 43, using insulated stranded wire 

 rather than solid wire, since it is more pliable. Do not remove the paper cartons 

 which are needed for proper insulation and take care that the adjacent zinc binding 

 posts do not touch. 



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