F.\ci.\'F.r.Rixc. COST srmir.s =, 



(f) ApartnuMits. 

 (i\) l.<Hli;iii,k; lloiisis. 



Ill f.uli tl.i-is, Mil>»li\ i>ioiis .no lu.uli- .urnriliiij; lo llic i»-iil p.iid 

 as it has bivn foiiiul thai a ilosi- rrlation exists hoiwi-cn ront and (hi- 

 class of ti'li'plioiio sor\icc iisi-d. Husincss ti-lcphoiu's an- dividi'd 

 iiiti) 21) or M) dirtVrt'nt dasst-s. An important factor in the forecast Ls 

 the future population of the city, both as a whole and l)\- sections! 



This involves, in each particular problem, not only study of the 

 past growth of the city in <iuestion, but also careful and detailed 

 comparis<ins with the growth history of other cities where condi- 

 tions have been such that the experience in those places is usefid 

 in making the pretliction for the city being studied. 



Having arrived at forecasts, for certain future dates, as to the 

 number of telephone users to be providc<l for, where they will be 

 locatetl. what character of service they will recpiire, what time of 

 day they will call, and how freiiuently, and where they will call, it 

 lHHX)mes a definite, although intricate engineering problem to de- 

 termine the most economical number, size and location of buildings 

 and switchboards and the location and size of conduit runs. All of 

 the promising combinations of future offices and districts as indi- 

 cateil by experience anil the geographical characteristics of the city, 

 are laid out on working maps and the annual costs are figured. The 

 arrangement which gives the lowest equated annual costs o\er tiie 

 pericxi of time for which the stutly is made is, in general, the one 

 which is adopted. Fundamental plans are reviewed every few years, 

 particularly when some major plant addition, for example, the open- 

 ing of a new central otlice, comes up for consideration. In this way 

 we are constantly looking ahead and following a coordinated plan; 

 but this plan is not a rigid, fi.xed thing. It is modified as frequenth' 

 as may be necessary to meet the constantly changing requirements. 

 In work of this kind, future expenditures must be given greater or 

 less weight accordingly as they are required to be made in the near 

 future or at some more distant time. This is taken into account b\- 

 equating future expenditures in terms of their present worth; that 

 is, the sum in hand, at the present time, which, at compound interest, 

 will be just sufficient to proxide for the future expenditures when 

 they are required. 



Transmission St.vnd.vrds .and Stiuies 



-An interesting and typical annual cost problem which arises in 

 connection with fundamental plans is that of obtaining a proper cost 



