Pacific Bell has millions of phone calls that cannot routinely be charged. Investigators manually search for clues that allow unbilled charges to be correctly charged before the state regulated time period expires. In order to recover billable revenue Pacific Bell elected to bring additional automated support to the problem. As a result, Pacific Bell chose to implement an expert system, the Expert Message Correction System (EMCS). EMCS was deployed in November 1993, and is currently processing thousands of unidentified calls each day. The EMCS architecture involves access to multiple mainframe applications and databases, and incorporates a multi-process architecture that automatically selects and schedules multiple expert system processes to execute within a single workstation. This design provides a high degree of parallelism to enable processing the large volumes of calls and their associated mainframe data. In addition to this multi-process architecture, EMCS provides new uses of Al technology in the telecommunications industry, particularly in the areas of billing.