| 710 / | HD | ELECTRICAL COMPUTERS AND DIGITAL DATA PROCESSING SYSTEMS: INPUT/OUTPUT |
| 100 | DF | INTRASYSTEM CONNECTION (E.G., BUS AND BUS TRANSACTION PROCESSING) {7} |
| 101 | DF | .~ Bus expansion or extension {1} |
| 102 | DF | .~.~ Card insertion {1} |
| 103 | ![]() | .~.~.~ Hot insertion |