CENTRALIZED AUTOMATIC MESSAGE ACCOUXTIXG SYSTEM 



1335 



flat rate calls from all types of central offices, and to customer dialing of 

 message unit and toll calls from central offices using one of the present 

 methods of charging. 



FIELD OF USE FOR THE CAMA SYSTEM 



The CAMA system, as now developed, is suitable for use in panel- 

 crossbar local areas. It is arranged to serve 7-digit calls only since fa- 

 cilities for 10-digit dialing are not available for panel and No. 1 crossbar 

 central offices. Thus, in general, it can complete calls only to its own 

 numbering area. However, provision is made for completing calls to one 

 adjacent area, this area being selected by dialing "one-one" ahead of 

 the listed 7-digit number. 



BRIEF DESCRIPTION OF THE CAMA SY'STEM 



If a customer makes a call that requires CAMA treatment, the call 

 will be routed by the local central office to a crossbar tandem office 

 arranged for CAMA recording. Until automatic means for identifying 

 the calling customer's number for billing purposes is developed, an oper- 

 ator will be bridged on the connection at the tandem office to obtain the 

 calling number and register it in the CAMA equipment by keying. The 



CALLING 

 TELEPHONE 



ORIGINATING 



CENTRAL 

 OFFICE 



CROSSBAR 

 TANDEM OFFICE 



SWITCHING 

 EQUIPMENT 



OPERATOR'S 



POSITION 



TO 



NATIONWIDE 



TOLL NETWORK 



Fig. 2 — Simplified switching diagram. 



