Automatic Number Identification and Its Application to No. 1 Crossbar, Panel and Step-by Step Offices

01 September 1958

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As the range of customer dialing has been extended, it has become increasingly important to provide arrangements for automatically recording and processing the data required for billing these calls. To accomplish this, a system using punched tape recording and known as automatic message accounting (AMA) has been developed. This system has been arranged for local office application in No. 1 crossbar, No. 5 crossbar and step-by-step offices. Here, automatic number identification is an integral part of the system. This application is economical only when calling rates for customer-dialed multiunit traffic and toll traffic are relatively high; in places where the calling rate is low, AM A features may be located more economically at a tandem or toll-switching location. This is known as centralized automatic message accounting (CAMA). In its earlier arrangement, an operator has been bridged on the connection momentarily to obtain the calling number and to key it into the system. Automatic means of performing this action have been developed 1295