A wireless machine monitoring and communication system includes one or more machine monitors which attach to one or more machines to sense a physical characteristic of the machine, such as vibration or temperature, and to produce wireless transmissions corresponding to the sensed characteristic. A command station executes machine status polling in accordance with a time-division communication protocol and processes machine status data obtained during polling to determine the status of the machine. The machine monitor incorporates a wireless transmitter for transmitting at least status information, and the command station incorporates a wireless receiver for receiving monitor transmissions. To conserve power, the machine monitors are turned on only at preprogrammed times in accordance with the time-division communication protocol. Each machine monitor includes a receiver and the command station includes a transmitter to enable the command station to send commands to each machine monitor. A microcomputer in each monitor analyzes sensor data and a memory stores the analyzed sensor data. Repeaters are employed as necessary to assist in propagating wireless transmissions throughout the system. A tachometer sensor is employed at each machine to provide monitors and sensors with information relating to machine speed. A computer network is connected to the command station for transferring data and for controlling the overall operation of the system.