Either method provides some protection from power failures. A standalone computer system running call accounting software is attached directly to the SMDR port. Records are stored to hard disk immediately. Analysis and reporting proceeds from the console, or through workstations attached to the main system over the network. As call records are captured, the call accounting system decodes them and converts them to database records - usually in a standard format.
Further analysis is performed on the converted database.
Your call accounting system must be configured with data pertinent to the kinds of analysis you need performed. These are provided by the call accounting vendor, and should be periodically updated. The most sophisticated call accounting products are offered as modules of large-scale telemanagement suites. They share data with facilities management, directory management, and other modules. The cost of calls should be allocated to the products you're making, or the departments or divisions in your company.