A monitoring system is disclosed for producing an alarm at a central station when a monitored condition at a monitor station deviates beyond a predetermined limit. The monitor system is especially adapted for monitoring a vital function of plural patients in a hospital so that a single attendant is alerted if any patient needs emergency treatment. The monitor unit is portable by the patient, suitably in the form of a wrist-unit, and a communications link, suitably by radio frequency transmission, is provided for one-way transmission from the monitor station to the central station. Each monitor station develops and processes data to determine whether the monitored condition has a value exceeding a predetermined limit; if so, an identification signal is transmitted to the central station to signify that an emergency exists at that monitor station. Each monitor station includes a programmed data processor to eliminate the need for transmitting variable data to the central station. Only fixed or stored data is transmitted for the purpose of identifying the monitor station. The processor electronics is suitably implemented in large scale integrated circuitry.