Detailed answer:
EN 55022 is named "Information technology equipment – Radio disturbance characteristics" and it covers the radiation of EMI (Electro-Magnetic Interference)
The standard defines 2 classes: A and B.
- Devices of class B are intended to be used in living areas, usually offices or private homes. These devices cannot tolerate much EMI and thus they are not allowed to transmit much EMI.
- Devices of class A are for industrial use. They are allowed to transmit a bit more EMI than class B devices, because they can also tolerate more EMI.