| 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} | 
| 250.1 |  | .~.~.~.~ Automatic gain control to improve strong signal handling |