| 340 / | HD | COMMUNICATIONS: ELECTRICAL |
| 500 | DF | CONDITION RESPONSIVE INDICATING SYSTEM {6} |
| 501 | DF | .~ With particular system function (e.g., temperature compensation, calibration) {8} |
| 514 | ![]() | .~.~ Testing {2} |
| 515 | DF | .~.~.~> Simulation of condition |
| 516 | DF | .~.~.~> Automatic (e.g., periodic, start-up) |