Centralized data communications network method using first- and

Abstract

The Centralized Management System utilizing a Bus Interface Unit comprises a Computer (4z) installing an address Bus (4a), data Bus (4b), and control Bus (4c), a First-Level Station (4Q1) communicating with the Computer (4z) as the First-Level Station (4Q1) is connected to the buses (4a, 4b, 4c) of the Computer (4z), a plurality of second-level stations (4Q2, 4Q3, . . . , 4QM) communicating with the First-Level Station (4Q1) as the second-level stations (4Q2, 4Q3, . . . , 4QM) are connected to the First-Level Station through a Multipoint Bus (4r). Therefore, the Centralized Management System is capable of communicating the Computer with the First-Level Station through a Dual Port RAM (Random Access Memory), intercommunicating a plurality of Second-Level Stations through a Multipoint Interface and Multipoint Bus, and controlling and managing several thousands of Terminals (for example, Public Telephones). An operating method of the above system includes initializing the computer from a start signal, sending commands that instruct tasks to the first-level station through the dual port RAM, checking the response from the first-level station, performing programs related to the instructed tasks when there is a response from the first-level station, checking whether the instructed tasks are completed, and checking whether another task is instructed, and if so, sending commands to the first-level station, or terminating the process when no other task is instructed.