A patient monitor system synchronizes patient data acquired by a plurality of sensor modules. Patient data from the sensor modules are synchronized by transmitting, from a patient monitor host, a start message that each newly connected sensor module uses to determine when to begin transmitting patient data to the patient monitor host. At a predetermined count interval, the patient monitor host also broadcasts an incrementing sequence count value to each of the connected sensor modules. The sensor modules use the sequence count values and the start message to determine when the patient monitor host expects each sensor module to transmit data packets. Each data packet sent by the sensor modules includes a sequence count value that the patient monitor host uses to align the various waveforms for display.