| 370 / | HD | MULTIPLEX COMMUNICATIONS |
| FOR 101 | ![]() | MULTIPLEX SWITCHING (370/53) {5} |
| FOR 102 | DF | .~> Pathfinding (370/54) |
| FOR 103 | DF | .~> Drop channel (370/55) |
| FOR 104 | DF | .~> Concentrators (370/56) |
| FOR 105 | DF | .~> FDM switching (frequency division multiplexing) (370/57) |
| FOR 106 | DF | .~> TDM switching (time division multiplexing) (370/58.1) {12} |