| 340 / | HD | COMMUNICATIONS: ELECTRICAL |
| 825 | DF | SELECTIVE {23} |
| 825.57 | ![]() | .~ Pulse responsive actuation {5} |
| 825.58 | DF | .~.~> Phase or frequency shift keying |
| 825.59 | DF | .~.~> Polarity |
| 825.6 | DF | .~.~> Pulse pairs |
| 825.61 | DF | .~.~> Having delay line |
| 825.62 | DF | .~.~> Serial {5} |