| 379 / | HD | TELEPHONIC COMMUNICATIONS |
|
| 242 | DF | CENTRALIZED SWITCHING SYSTEM {15} |
| 258 | DF | .~ Switching controlled in response to called station addressing signal {9} |
| 268 | DF | .~.~ Having shared or common switching control {8} |
| 280 |  | .~.~.~ Including registering or storing device for call address signal {7} |
| 281 | DF | .~.~.~.~> Conversion between dial pulse and voice frequency signal |
| 282 | DF | .~.~.~.~> Voice frequency receiver {1} |
| 284 | DF | .~.~.~.~> With processor |
| 285 | DF | .~.~.~.~> With magnetic memory |
| 286 | DF | .~.~.~.~> Signal processing (e.g., dial pulse analysis) |
| 287 | DF | .~.~.~.~> Electronic |
| 288 | DF | .~.~.~.~> Register-sender |