There are two types of crosstalk:
- Near-End Crosstalk (NEXT)
- Far-End Crosstalk (FEXT)
Twisted Pair Categories
| Cat Category | Status | Max. Frequency | Transmission Speed | Max. Length |
| 1 | Deprecated | |||
| 2 | Deprecated | |||
| 3 | Active | 16 MHz | 10 Mbps | 10 Mbps |
| 4 | Deprecated | 20 MHz | ||
| 5 | Deprecated | 100 MHz | ||
| 5e | Active | 100 MHz | 1 Gbps | |
| 6 | Active | 250 MHz | 10 Gbps | 55 m |
| 6a | Active | 500 MHz | 10 Gbps | 100 m |
| 7 | Deprecated | 600 MHz | 10 Gbps | |
| 7a | Deprecated | 1000 MHz |
Cat5e twisted pair has a maximum speed of 1,000 Mbps. The “e” comes from enhanced. It arrived in 2001.
Cat6 twisted pair has a maximum speed of 10,000 Mbps.
Cat6 and Cat6a could be either shielded or unshielded.
Cat7 reaches 10.000 Mbps speed.
Types
Unshielded twisted pair (UTP)
Shielded Twisted Pair (STP)
Foiled Twitsted Pair (FTP)