522 liF.I.I. SYSTEM TECIIMCAL JOVRSAL 



results of his engineering effort should insure a service which is satis- 

 factory from the subscriber's viewpoint. 



It is evident from what has been said, I believe, that these engineer- 

 ing cost studies are of great benefit in working out the proper pro- 

 cedure in our engineering work, and I assume the\' arc equally helpful 

 in the engineering of any kind of growing plant. .Anything that can 

 reasonably be done, therefore, to gi\e the student an appreciation 

 of the nature, scope, and application of the economic considerations 

 of these engineering problems and to develop his faculties of judgment, 

 imagination, team pla\-, and other related qualities, will doubtless 

 pro\e of great value to the student in iiis later engineering work. 



()TIIi;k I'H.\SES OF ENGINliKKINc; WoKK 



I ha\e thus far described to you some of the \ery important engineer- 

 ing problems involved in the planning and carrv'ing out of plant exten- 

 sions to meet expected future ser\-ice requirements. I would like 

 next to consider with you a few of the engineering problems that present 

 themselves in the actual design or oper.itioii of these large extensions 

 to plant as introduced. 



'{"he rapid (k'v cldpnuiil nf ilu' lelepliime sysliMU, inrhuling llie tre- 

 mendous growth in the luuiiber of lelei)liones in service and the rapid 

 increase in the extent of territory which can be reached from any 

 telephone, has led to a great increase in the imjiortance and difficulty 

 of the technical jjroblems involved in tiie design and ni.iintenance 

 of the plant. 



These technical probli-ms cover a vi'ry wide rangt.'. The electrical 

 and acoustic problems involved in the transmission of speech have 

 led telephone men to much pioneering work dealing with the flow of 

 sustained and transient alternating currents in electric circuits of all 

 types and in the fundamental nature of speech and hearing itself. 

 .Again, the economical design of outside plant with suitable strength 

 and economy involves investigations of characteristics of construction 

 and materials and the preservation of limber, and there are, of course, 

 special mathematical ancl other problems involved in the design of long 

 cable or wire spans. Buildings and associated central office equip- 

 ments involve very interesting mechanical and electrical jiroblems 

 in the matter of the layout ofthe buildings and the arrangement of 

 a|)paratus to meet exacting re(|uirements. These include many 

 problems in the design of means for automatically supervising the 

 |)rogress of telephone connections anil in the design of thousands 



