5ESSOverview :-The 5ESS-2000 Switch is a digital exchange that can serve as a local(lines),toll(trunks), tandem(lines and trunks), OSPS(operator Service PositionSystem) or international gateway exchange, depending on the type ofswitch. It can serve a small community with fewer than 100 subscribers or alarge metropolitan area serving more than 100,000 subscribers.Modular Distributed Design :-The 5ESS- 2000 switch is a digital switching with distributed processing.Distributed processing means that multiple processors handle all callprocessing functions. Many processors are distributed throughout the systemsupported by a central processor. These distributed processors handlesecond-to-second decisions that must be made to process a call. Callprocessing, self maintenance, and testing are performed independently ineach module. Processors communicate with each other via an internaldigital network that links the module together.The 5 ESS 2000 Switch hardware has three major types of equipment