TRUNK REQUIREMENTS IN ALTERNATE ROUTING NETWOKKS 801 



levels can and do change with the years tor a Naricty ol reasons thus 

 automatically changing the cost comparison. 



In spite of the difficulties in ohtainiiig a true and stable conipaiison 

 of the overall costs of the two methods the weight of evidenct; indicated 

 the desirability of proceeding with the plans for achieving an ultimate 

 goal of nationwide toll dialing employing the technicjues of multi-alter- 

 nate routing in the design of the intertoU tiunk ncUwork. 



With the completion of the study of the \arious intertoU trunk re- 

 (luirements for nationwide operator toll dialing there was established 

 for the first time a bench-mark against which many of the assumptions, 

 theories and procedures which went into its making could be measured 

 for accuracy and practicabilit3^ Among these was the early question re- 

 garding the cost of operator toll dialing with engineered alternate routing 

 compared to its cost without alternate routing. To arrive at a complete 

 answer it would be necessary to restudy the entire network on the current 

 basis of trunking, compare costs of dial switching eciuipment without 

 CSP features with the cost of CSP switching equipment, evaluate 

 changes in the location and tj'^pes of trunk facilities and so on. The under- 

 taking of a stud}^ and analysis of this scope would recjuire a larger ex- 

 penditure of engineering time and effort than would seem justified by 

 the usefulness of the results. It should be noted, however, that analysis 

 of the alternate routing trunk study indicated that the original premise 

 as to trunk economies to be expected were substantially correct. In any 

 event the advent of customer toll dialing with its peremptory require- 

 ment for high speed trunking has rendered the original ciuestion of the 

 relative costs of operator toll dialing, with and without engineered alter- 

 nate routing, somewhat academic. It can be safely assumed that a high 

 speed intertoU trunking system suitable for customer dialing and engi- 

 neered without alternate routing would be prohibitive in cost. 



CONCLUSION 



The transition from ringdown (wholly manual) handling of long haul 

 toll traffic to operator dialing of such traffic has been proceeding for 

 many years and at an increasingly greater rate during the last five years 

 until now some 45 per cent of such traffic is dialed by operators. This has 

 been accomplished almost exclusi\'ely on trunk networks operated with- 

 out benefit of engineered alternate routing. Along with this, increasing 

 use of dialing by destination code has been achieved as various cities 

 and areas h&xe converted to the nationwide nimibering plan. 



The second phase of the transition, now under way, involves the 

 change from non-alternate routing to alternate routing trunking. With 



