880 THE BELL SYSTEM TECHNICAL JOURNAL, SEPTEMBER 1952 



system, arrangements were included for sending forward the complete 

 number, as received, to the toll office by MF pulsing. The system was 

 also designed to be capable of automatic alternate routing and this 

 feature is used in the trial. 



Expansion of the program will, of course, demand that similar ar- 

 rangements be provided for the older types of local switching systems 

 already in service. More extensive modification will be required to make 

 them capable of giving the customer the same service. For them, as for 

 the most modern system, however, AMA equipment is admirable for 

 recording the information necessary for charging for the calls. 



The requirement for customer toll dialing that senders (or directors) 

 and recording equipment be provided has a bearing on the type of 

 equipment used at TC's and TO's. For calls handled by operators and 

 for calls received by the customers through such offices the only disad- 

 vantage of step-by-step ec^uipment without senders at those points is 

 that the CSP equipment at other points must be somewhat more com- 

 plicated and expensive than it would otherwise need to be. But with 

 customer dialing, if senders and recording equipment are not provided 

 either in the local office or in the TC or TO, the calls must be routed by 

 the most direct means possible to a CSP where such equipment is pro- 

 vided. Thus some advantages that might be gained from having them 

 at the TC or TO would be lost: 



1. In some cases an indirect route to the CSP would need to be taken 

 for the sole purpose of recording the call. For example, a call which 

 might normally be switched from a TC through a TO to another TC 

 would need to be connected to the CSP for making the record. 



Fig. 8 — Card for the new trouble reco 



