The Signet 3300 Ultrasonic Flow Monitoring System advances the use of Doppler ultrasound technology in flow measurement by utilizing proprietary "Advance Spectrum" signal processing in measuring the entire flow stream. The result is reliable, power-efficient, low cost of ownership, liquid flow monitoring in open or closed channels. The Signet 3300 includes features tailored to meet common requirements in a variety of applications like municipal water/wastewater, industrial waste, etc. The Signet 3300 system can be equipped with up to four 4 to 20mA outputs for interfacing to loggers, telemetry systems or PLC's for long-term monitoring or an RS232 local connection to laptops or pocket PCs. Pulse output is standard. This vandal resistant unit features dual password protected local or remote downloading of logged data. Both velocity and velocity/depth combination sensors have no moving parts and lend minimal obstruction in the flow stream.