| 370 / | HD | MULTIPLEX COMMUNICATIONS | 
| 431 | DF | CHANNEL ASSIGNMENT TECHNIQUES {12} | 
| 449 | DF | .~ Polling {1} | 
| 450 | DF | .~.~ Passing a signal identifying the idle or busy state of a channel (e.g., token passing) {2} | 
| 451 | DF | .~.~.~ On bus {1} | 
| 452 | DF | .~.~.~.~ On ring or loop {4} | 
| 453 |  | .~.~.~.~.~ Initialization or reinitialization of network |