Q. Explain about Stored Program Control?

Stored Program Control:  In centralized control, all control equipment is replaced by a single processor which should be quite powerful. It should be capable of processing 10 to 100 calls per second, depending on the load on system, and concurrently performing many other  ancillary  tasks. A typical  control configuration of an ESS using centralized SPC is displayed in Figure. A centralized SPC configuration can use more than one processor for redundancy purposes. In almost all present day electronic switching systems employing centralized control, only a two-processor configuration is used. A dual  processor architecture can be configured to operate in one of three modes:

(i)  Standby mode

(ii)  Synchronous duplex mode

(iii)  Load Sharing mode