Communications for a county emergency medical services (EMS) system

Emergency medical services (EMS) communications systems implemented in San Mateo County, CA, between 1976 and 1978 are described. The author was Supervisor of Communications for the Country of San Mateo from September 1973 to June 1978. During this time, EMS radio systems were planned and implemented to serve the county in accordance with the EMS Communications Regional Plan for the nine-county San Francisco area. The San Francisco Bay area actually comprises four U.S. Department of Health, Education and Welfare regions, but operates under one common communications plan for the use of the UHF MED channels. Three radio systems were set up to handle 1) dispatch and coordination, 2) patient delivery and coordination of hospitals, and 3) direct physician medical control of field paramedics. The first two systems each use a 482/485-MHz frequency pair in a multisite receiver voting with simulcast transmitting equipment configuration. The third radio system uses the UHF MED 1-8 channels for physician control of field care with 10-channel base stations at strategic locations. The factors influencing system design and technical factors of the systems are discussed. Also discussed are citizen access to the system, and coordination with adjacent counties on the shared use of the MED 1-8.