| 455 / | HD | TELECOMMUNICATIONS |
| 130 | DF | RECEIVER OR ANALOG MODULATED SIGNAL FREQUENCY CONVERTER {24} |
| 230 | DF | .~ Local control of receiver operation {7} |
| 232.1 | DF | .~.~ Gain control {2} |
| 234.1 | DF | .~.~.~ Automatic {15} |
| 239.1 | DF | .~.~.~.~ Nonlinear automatic gain control {4} |
| 242.1 | | .~.~.~.~.~ Delayed {2} |
| 242.2 | DF | .~.~.~.~.~.~> Different delay for different signal stages or thresholds |
| 243.1 | DF | .~.~.~.~.~.~> Radio frequency stage only delayed |