What is Cat6 cable?
Cat6, or Category 6, is a twisted-pair copper cabling standard in the TIA-568 family, rated for frequencies up to 250 MHz, two and a half times Cat5e's 100 MHz. It also has tighter limits on crosstalk than Cat5e. Many Cat6 cables have a plastic spline (separator) down the middle to keep the pairs apart, and many use slightly thicker conductors than Cat5e, often 23 AWG.
Cat6 terminates with RJ45 connectors, wired to the T568A or T568B standard like other Ethernet cable.
Speed and distance
- 1 Gbps (1000BASE-T) over the full 100-meter channel.
- 2.5 Gbps and 5 Gbps (2.5GBASE-T and 5GBASE-T) over 100 meters.
- 10 Gbps (10GBASE-T) only on shorter runs, up to about 55 meters, depending on installation conditions such as alien crosstalk between neighboring cables in a bundle.
For 10 Gbps over the full 100 meters, you need Cat6a.
Cat6 compared with other categories
| Category | Bandwidth | Typical top speed | Distance |
|---|---|---|---|
| Cat5e | 100 MHz | 1 Gbps | 100 m |
| Cat6 | 250 MHz | 1 Gbps (10 Gbps on short runs) | 100 m at 1 Gbps; about 55 m at 10 Gbps |
| Cat6a | 500 MHz | 10 Gbps | 100 m |
| Cat8 | 2,000 MHz | 25 or 40 Gbps | 30 m |
Installation tips
- A link is only as good as its weakest part. Cat6 cable punched down on Cat5e jacks or patch panels performs as Cat5e, so use Cat6-rated jacks, panels and patch cords.
- Untwist as little of each pair as possible at terminations, and don't exceed the cable's bend radius or crush it with tight cable ties.
- Pick the jacket rating for the space: plenum (CMP) above return-air ceilings, riser (CMR) between floors.
For the CompTIA A+ exam
Core 1 (220-1201) objective 3.2 covers copper cable categories and the T568A/T568B wiring standards. The classic trap is Cat6 versus Cat6a: both can carry 10 Gbps, but only Cat6a is rated to do it over the full 100 meters. If a question asks for the minimum cable for 10 Gbps at 100 meters, choose Cat6a.