supervisory signal
supervisory signal
[¦sü·pər¦vīz·ə·rē ′sig·nəl] (electricity)
A signal which indicates the operating condition of a circuit or a combination of circuits in a switching apparatus or other electrical equipment to an attendant.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.