Electromagnetic radiation emitted into the atmosphere from the power supply. Conducted is that energy sent down the AC line cord; radiated is sent into the air. Adaptors must meet both but many open frame switchers are only rated for conducted (the assumption being that they will be placed into the customerâ€(tm)s box).
Intensity of radiation in places where people are present.
Electromagnetic interference being produced by the device, either radiated through the air and conducted along power and signal lines and enclosures.