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Automatic Intercept System: Organization and Objectives

01 January 1974

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Copyright © 1974, American Telephone, and Telegraph Company. Printed in U.S.A. Automatic Intercept System: Organization and Objectives By C. J. BYRNE, W. A. WINCKELMANN, and R. M. WOLFE (Manuscript received A p r i l 12, 1973) The Automatic Intercept System routes calls to nonworking telephone numbers to a centralized location where a time division network under stored program control connects the calling customer to a series of prerecorded announcements. The customer is told what number he reached and, from information stored in a large-capacity disc file, is given the reason the number is not in service and, if available, the new number at which the called party may be reached. This paper describes the system objectives and organization and also serves as an introduction to the detailed papers which follow. I. I N T R O D U C T I O N 1.1 General Each customer's line in the telephone switching network is identified by a unique seven-digit number within a three-digit area code. The first three digits designate the local switching center or "office" in which the customer's line terminates, and the remaining four digits identify the customer within that switching center. Of the 10,000 possible telephone numbers associated with an office code, some 1000 1 or more are not actually assigned at any given time. Many numbers have been disconnected as customers move, other numbers have been changed, and some offices are only partially equipped, with blocks of numbers not existing in a particular office.