534 BEI.l. SYSTEM TECIIMCAL JOURNAL 



Due to the large area in\-ol\'C(l. a great number of rails within the city 

 necessitates extra charges, which means that they must he specially 

 supervised and recorded. There arc man\- different classes of service 

 furnished the public, such as measured rate, flat rate, coinbox, etc., 

 and, of course, such other special services as Information service. 

 Not only individual lines but party lines and pri\ate exchanges must 

 be cared for. Furthermore, the demands for ser\ice to the extensive 

 area surrounding this great city, as well as the large number of cities, 

 towns and rural communities throughout the entire country. ri-(|uirt' 

 that provision be made ft)r thousands of toll mes.sagcs daiK'. Tlu- 

 problem of gi\ing satisfactory service under these conditions and uiuler 

 the com])lications that come with the tremendous growth referred 

 to is a very important one and requires careful and constant stud\-. 



In order to properly care for this complex prolilem of furnishing 

 telephone service in large cities, telephone engineers in line with the 

 efforts which ha\'e been made from the time of the early switchboards 

 have endea\ored to perform the \arious operations automaticalh' so 

 far as consistent with serxice requirements. While the switchboards 

 which you saw yesterday are called "manual" switchboards, you 

 doubtless noted from the demonstration and your visit through the 

 central office that many of the operating features are automatic in 

 character. The latest step in this general trend of development has 

 been to develop a switchboarti which would pro\ide for completing 

 many classes of calls entirely without the aid of an operator, and these 

 new machine switching equipments which you will see today are 

 gradually being introduced into .\ew V'ork, Chicago, and other large 

 cities. This is a large problem in itself and involves not only the 

 completion of calls from machine switching subscribers to other 

 machine switching subscribers, but the completion of calls incoming to 

 machine switching offices from manual offices and outgoing to manual 

 offices. This must be done without reaction on the service or in- 

 con\enience to the subscribers and so that the machine equipment 

 and the manually operated switchboards will work together as a co- 

 ordinated whole. 



I do not know of any mechanical device that reminds one so much 

 of the functioning of the human brain as does this mechanism for 

 completing calls following the dialing operation. The completion 

 of a simple call, while quite in\olved in itself, is by no means the 

 complete [iroblem. There must be a great many other features pro- 

 vidtnl, such, ft)r one example, as where a register is provided on the 

 subscriber's line to register the number of calls under measured rate 

 service. In these cases it is necessary to insure that there shall be 



