« Class » means something completely different than « category ».
The class (or category link in American English) always applies to the installed link, the category as such applies only to one single component, e.g. the cable or the outlet; the component is tested and verified by either the labs of the manufacturer or independent verification labs.
The installed link is always tested according to classes (or category links).
| Cabling classes according to ISO / IEC | Component categories according to ISO / IEC |
| Class D: frequency range up to 100 MHz, for data rates up to 1 Gbps | Category 5: frequency range up to 100 MHz, for data rates up to 1 Gbps |
| Class E: frequency range up to 250 MHz, for data rates up to 1 Gbps | Category 6: frequency range up to 250 MHz, for data rates up to 1 Gbps |
| Class EA: frequency range up to 500 MHz, for data rates up to 10 Gbps | Category 6A: frequency range up to 500 MHz, for data rates up to 10 Gbps |
| Class F: frequency range up to 600 MHz, for multi-media applications | Category 7: frequency range up to 600 MHz, for multi-media applications |
| Class FA: frequency range up to 1,000 MHz, for multi-media applications | Category 7A: frequency range up to 1,000 MHz, for multi-media applications |
