340 / | HD | COMMUNICATIONS: ELECTRICAL |
500 | DF | CONDITION RESPONSIVE INDICATING SYSTEM {6} |
540 | DF | .~ Specific condition {18} |
584 | DF | .~.~ Thermal {8} |
595 | .~.~.~ Current modifier or generator {4} | |
596 | DF | .~.~.~.~> Cable or elongated probe |
597 | DF | .~.~.~.~> Curie point sensor |
598 | DF | .~.~.~.~> Barrier-layer sensor |
599 | DF | .~.~.~.~> Bridge circuit |