| 360 / | HD | DYNAMIC MAGNETIC INFORMATION STORAGE OR RETRIEVAL |
| 69 | DF | AUTOMATIC CONTROL OF A RECORDER MECHANISM {3} |
| 71 | DF | .~ Controlling the record {3} |
| 73.01 | ![]() | .~.~ Speed {3} |
| 73.02 | DF | .~.~.~> Control of relative speed between carriers |
| 73.03 | DF | .~.~.~> Rotary carrier |
| 73.04 | DF | .~.~.~> Linear carrier {2} |