FUNDAMENTAL PLANS FOR TOLL TELEPHONE PLANT 841 



area and to such points as Baltimore and Ainiapolis. The favorable 

 results and general acceptance of the trial at T^nglewood indicate ex- 

 tensive application of customer dialing of toll calls as conditions warrant. 



The general introduction of customer toll dialing as this becomes 

 desirable will affect the lunnber and location of ordinary toll centers 

 since calls handled by operators may be limited to assistance calls and 

 to person-to-person, collect and others which cannot be customer dialed. 

 Indications are that toll operation for a number of smaller centers can 

 be combined as the local service is converted to dial operation with 

 operator toll dialing. 



Studies now in progress indicate that the lumiber of toll centers may 

 be reduced by one half or more over a period of years in many areas. 



Reactions on Toll Plant Layout 



The expanded general toll switching plan for nationwide dialing con- 

 templates a degree of alternate routing far in excess of that used with 

 the former switching plan designed for manual operation. This change 

 along with the reduction in toll centers will have a marked effect on the 

 normal flow of many traffic items through the intertoll network. As a 

 result the arrangement of the present intertoll trunks will be significantly 

 modified both in number, routing and terminating points. It is necessary 

 to take these facts into account in engineering toll plant additions so 

 that they will lead toward an advantageous layout for future nationwide 

 dialing as well as meet the needs of the more immediate future. Fortun- 

 ately, the effect is in the direction of greater concentration of circuits 

 in main routes so that with the new cable and radio facilities available, 

 o\er-aIl economy and better service should result. 



TYPES OF TRANSMISSION FACILITIES USED AND INCLUDED IN SWITCHING 

 PLAN 



The domestic toll network is an outgrowth of the demands of the 

 business and the advance in communication technique over many years. 

 At present, about 100,000 intertoll trunks over twenty-five miles in 

 length and many thousand shorter toll trunks are in service throughout 

 the countrj'. They are provided generally by voice frequency or carrier 

 frequency facilities. The choice of transmission facility on a given route 

 is dependent on a number of factors, such as cost, length of haul, luimber 

 of trunks in the cross-section, numbers of trunks to be terminated at 

 intermediate points, the types of terrain to be transversed, storm and 



