Monitors, members of the Data Caste, spend their careers in the Hall of Records in Iacon, under the watchful eye of Alpha Trion, the Archivist of Iacon. They monitor transmissions over the Communication Grid that spans all of Cybertron. If a transmission meets a certain set of unknown criteria, a monitor will listen to it, annotate it, categorize it, and save it in a sector of the DataNet. After this, transmissions will mostly go on unnoticed, unless a cultural investigator wants to investigate something to do with culture, or the High Council wants to research something.
Orion Pax originated in the ranks of the monitors. While working at the Hall of Records, he met Jazz and had his first conversations with the upstart Megatronus. During the war, when Optimus Prime visited the Hall, the young monitors were awed that the great leader had rose from their ranks.