Telemetering circuits — Metallic and carrier

The art of telemetering has enjoyed a steady development for 30 years. The increased number of power system interconnections and the increased operating efficiency that is to be gained by use of automatic load control warrant careful study of the circuits that are used to transmit the required information. It is expected that as telemetering systems expand more multicircuit carrier channels will be used. Protective relay and communication circuits will be combined with telemetering circuits. Space radio probably will be added to provide trunk line service for communication, telemetering, supervisory, and protective relay control in locations that cannot be served economically by other means.