Once ignored by health care and management theorists, emergency medical service (EMS) has begun to attract attention to its traditional policies and practices. Long-standing notions about job qualifications, job responsibilities, organizational structure, and operations control are being challenged by alternative approaches such as System Status Management (SSM), Computer-Aided Dispatch (CAD), and Emergency Medical Dispatch (EMD). One important characteristic of these new models is their emphasis on the role of the communications center in controlling operations. Convincing arguments for these systems have been advanced, and they have been implemented successfully in many areas.Despite these developments, variations of the traditional model which minimizes the importance of the communications center and emphasizes control by field supervisors still characterize many, if not most, EMS systems in the United States. While this probably is due to a natural resistance to change and local political concerns, data supporting the new systems unfortunately are only anecdotal. Except for superficial comparisons, the traditional and alternative approaches have not been examined in light of accepted management theory and principles. Therefore, this paper will analyze the communications center and operations control from a theoretical standpoint to determine where in an EMS organization, control is exercised most naturally, and how these findings could impact on management effectiveness.