AUTOMATIC TOLL SWlTt'Hl.NG SYSTEMS 879 



offered to the group represented by it nor to any group ul)()ve it in the 

 fixed alternate I'oute pattern. This is done to relieve offices which are 

 overloaded by either untoi'eseen or predicted traffic peaks. 



MAINTENANCE 



The maintenance facilities for the new C'SP system are basically 

 similar to those of the older toll crossbar system with the lUM-essary ad- 

 dition of e(iuipment to test the new features introduced. The send(M' test 

 framc^ is, of course, ol)liged to test the ('8P ieatures added to the sender 

 and \\\v trouble indicatoi' frame is changed to operate with the new 

 decoders, translators and markers. 



In place of the lamp trouble indicator the new trouble leccjrdei' in- 

 troduced with the latest local crossbar system is used. Whene\'er trouble 

 is encountered it punches on a card a record of the circuits involved and 

 of the important events that had occurred in the progress of the call, 

 as an aid to the maintenance man in locating the trouble. A sample 

 ti'ouble recorder card is shown in Fig. 8. 



Automatic eciuipment for testing the operation and transmission fea- 

 tures of intertoll trunks has also been designed both for the older sys- 

 tems and for the new CSP system. 



SWITCHING ASPECTS OF CUSTOMER TOLL DIALING 



In the course of developing the switching system for CSP's the re- 

 quirement for handling long distance traffic dialed by customers as 

 well as that dialed bj^ operators was kept in mind. The trial of long dis- 

 tance customer dialing now in progress in Englewood, N. J., confirms 

 the soundness of the basic plan and exemplifies the principles involved 

 in full realization of the plan. With a toll network laid out to accept a 

 distinctive ten-digit number for any telephone in the country and route 

 it to the proper destination, the remaining tasks to be performed are to 

 provide for delivery of the number to the toll netw^ork from the cus- 

 tomer's dial instead of from an operator and to provide an automatic 

 record of the call for charging purposes. 



In Englewood both tasks were quite easily performed. The Englewood 

 local office eciuipment is of the most modern type and includes AMA* 

 facilities. When it was in the development stage the ultimate reciuirement 

 for nationwide customer dialing was foreseen and provision was made 

 for expanding the digit capacity of the switching equipment at small 

 expense. Also the designs of the accoiuiting center were such that corre- 

 sponding changes could readily be made. In the new local office switching 



