| 324 / | HD | ELECTRICITY: MEASURING AND TESTING | 
| 600 | DF | IMPEDANCE, ADMITTANCE OR OTHER QUANTITIES REPRESENTATIVE OF ELECTRICAL STIMULUS/RESPONSE RELATIONSHIPS {8} | 
| 629 | DF | .~ Distributive type parameters {6} | 
| 637 | DF | .~.~ Using transmitted or reflected microwaves {3} | 
| 639 | DF | .~.~.~ Where energy is transmitted through a test substance {2} | 
| 641 |  | .~.~.~.~ To determine insertion loss |