No. 1 ESS Master Control Center

Abstract

The no. 1 ESS master control center (MCC) serves as the interface between the switching system and operating telephone company personnel. It includes facilities for system test and control, alarm indication, maintenance of lines and trunks, recording customer billing information, and writing information on program store memory cards. The MCC is thus the central maintenance, control, and administration point of no. 1 ESS; it can be functionally divided as follows: (a) maintenance teletypewriter (TTY) facilities, the primary communication facilities between the system and operating company personnel. Other TTY channels provide for communication between the system and a number of other operating company areas (such as traffic measurement, line assignment, etc.). The description of all of these TTY channels is included. (b) alarm, display, and control circuitry to provide continuous indication of system status and permit maintenance personnel to control the system. (c) trunk and line test (TLT) facility provided for maintenance of trunks, lines and service circuits. Included are facilities for dc loop testing, transmission testing, circuit make-busy, handling permanent signals on lines, etc. (d) automatic message accounting (AMA) facility, providing a magnetic tape record of all data related to billing customer calls. The tape is processed in an accounting center to determine the customer charges. (e) program store card writer used for periodically updating the program store translation information. This machine is described in a companion paper.