Patent ID: 8493838

Claim:
A device management system for managing a plurality of devices respectively belonging to a plurality of management groups different from each other, said device management system comprising: a plurality of main units, a plurality of sub units, and an alternate unit, each of the main units comprises a respective main unit signal process unit including a respective main unit CPU, each of the sub units comprises a sub unit signal process unit including a respective sub unit CPU, a plurality of said main units being disposed in the plurality of management groups, respectively, a plurality of said main units comprises a first main unit disposed in a first management group, and a second main unit disposed in a second management group, a plurality of said sub units comprising at least one first sub unit disposed in the first management group, and at least one second sub unit disposed in the second management group, said first main unit being configured to perform communication with said first sub unit so as to perform management of said first sub unit, said second main unit being configured to perform communication with said second sub unit so as to perform management of said second sub unit, said first sub unit is connected to a first device belonging to said first management group, said first sub unit is configured to manage said first device according to the management of said first main unit, said second sub unit is connected to a second device belonging to said second management group, said second sub unit is configured to manage said second device according to the management of said second main unit, said alternate unit comprising a detection means and an alternate means, said detection means is configured to detect a failure of said first main unit, said detection means being configured to detect a failure of said second main unit, said alternate means being configured to perform communication with said first sub unit so as to perform management of said first sub unit when said detection means detects the failure of said first main unit, said alternate means being configured to perform communication with said second sub unit so as to perform management of said second sub unit when said detection means detects the failure of said second main unit.