What is ALERT?

ALERT stands for Automated Local Evaluation in Real-Time.  It is a radio protocol developed by the NWS in the late 1970s for transmitting hydrometeorological data.  Some of the hallmarks of ALERT are:

  • 300 BAUD
  • Sensor IDs from 1 – 8192
  • Sensor values are integers from 0 to 2047
  • ALOHA transmissions – They speak when they have something to say and they don’t know if their data was received
  • More than one base station can receive transmissions
  • Transmission is four (4) bytes of data per transmission, with three (3) bytes of content and the rest of the bits are marker bits.
  • Data can be lost because two sites can transmit at the same time causing a collision
  • Rain count protocol is resilient, if we miss a transmission, we catch up with the total on the next transmission

This protocol is used widely in the U.S. and Australia.  In Australia, they call it ERRTS.

Contact Us

Got questions? Send us an email and we'll get back to you shortly.

Start typing and press Enter to search