A personnel monitoring system includes a transmitting or transponding unit that is worn or carried by the individual being monitored. This transmitting or transponder unit periodically, or upon request, transmits a uniquely encoded signal that identifies the person being monitored, as well as information about the condition or activities of the person being monitored. Such condition or activites are sensed by sensors, coupled to the transmitting unit, that monitor selected body functions or parameters, such as heart rate, amount of skin perspiration, muscle movement, and the like. The monitoring system also includes a field monitoring device, or FMD, that is positioned near the person being monitored (or at a location where the person being monitored should be found). The FMD receives, processes, and stores the periodic or requested signals transmitted from the transmitting unit as directed by a program stored in a factory-removable and replaceable memory pack. Hence, the operation of the FMD can be changed as required in order to fit different monitoring applications. The monitoring system further includes a central processing unit, or CPU, that automatically, or by request, receives and interprets data from the FMD. The communication link between the FMD and the CPU may be by way of existing telephone lines or other telecommunicative links. From this data, the CPU generates desired reports indicating the location, condition, and activities of the monitored individual as a function of time.