CENTRALIZED AUTOMATIC MESSAGE ACCOUNTING SYSTEM 1341 



tomers in the area who are charged alike for their calls through the 

 tandem office. To actually determine the billing index or charge treat- 

 ment for each call, the rate treatment is modified by the called office code 

 by means of the rate treatment relays. Since calls with the same })illing 

 index may recjuire a 2-line entry if originated in some offices and 4-line 

 entry if originated in other offices, the billing index and calling office 

 code information are translated jointly by means of the entry combina- 

 tion relays to produce either the 2-line or 4-line indication. 



The recorder, call identity indexer and master timer circuits are of 

 the same type as used in local AIMA and perform the same functions. 

 The recorder perforates initial entries as directed by the transverter. It 

 also perforates a timing entry at the beginning of conversation and an- 

 other at the end of conversation. The call identity indexer, one of which 

 is associated with each recorder, identifies the trunk used on a call as a 

 particular one of the maximum 100 served by a recorder. This enables 

 the recorder to perforate that identity on initial and timing entries. The 

 identity is used by the accounting center to gather together the three 

 entries involved on each call. 



The master timer keeps the recorders continually informed as to the 

 correct time. 



When the initial entry is completely recorded on the AMA tape, the 

 sender completes its task of pulsing the called number forward and then 

 releases. The transmission path is now completed through the tandem 

 office and the only CAMA functions remaining are the perforations of 

 the timing entries mentioned above. 



ACCOUNTING CENTER PROCESS 



The accounting center process for CAMA is the same as for local 

 AMA. It automatically assembles the three bits of information pertain- 

 ing to each call, computes the conversation time on all calls, sorts by the 

 type of call, prices each call either in terms of message units for bulk- 

 billed calls or in ternis of dollars for detail billed toll calls and brings 

 together the records of all calls made by each customer. 



MAINTENANCE FEATURES 



To properly maintain the AMA recording facilities, test circuits are 

 provided for testing the major features of the CAMA equipment. An 

 automatic incoming trunk test circuit tests the CAMA trunks. An auto- 

 matic sender test circuit tests the CAMA senders in much the same way 

 that the present sender test circuit tests non-AMA senders. Facilities 

 are also provided for making operating tests of the position links, posi- 



