The purpose of the twists is to improve signal integrity by helping the cable reject interference. Higher cable grades have a higher number of twists per foot and, sometimes include guides that separate the pairs. Some cable types add foil shielding. The more twists and the more shielding, the higher the speed the cable will support.
How can you tell the capabilities of a cable? The industry has created specifications that tell us, such as CAT 5E, CAT 6, CAT 6A, CAT 7, CAT 7A and CAT 8.
CAT 5E vs. CAT 6 vs. CAT 6A vs. CAT 7 vs. CAT 8
Although CAT 5E has been widely deployed for more than 20 years, it’s unlikely to be used for new installations. CAT 5E supports up to 2.5Gbps over 100 meters. However, CAT 5E is more sensitive to interference than higher grades of cable, and it can struggle when pushed to its limits.
CAT 6 adds a pair-separating guide, helping it resist interference better than CAT 5E. CAT 6 supports 1Gbps up to 100 meters and 10Gbps up to 55 meters.
CAT 6A is similar to CAT 6, but increases the number of twists per foot and the gauge of the copper conductors, pushing 10Gbps up to 100 meters. CAT 6A is thicker and heavier than CAT 6.
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CAT 7 and CAT 7A are nonstandard cable specifications, independently created and not based on standards of the Institute of Electrical and Electronics Engineers. Most schools should ignore CAT 7 and CAT 7A cabling.
CAT 8 has a high number of twists per foot and multiple layers of shielding. There are two types of CAT 8: CAT 8.1 supports 25Gbps over 30 meters. CAT 8.2 supports 40Gbps over 30 meters. CAT 8 is thick, heavy and stiff compared with other cable types on this list, and it is costlier to install.
What Cable Category Makes Sense for Your District?
Choosing the right cable requires finding the right trade-off between speed, distance and longevity, while working within budget.
- More speed always feels like the right choice, but if the cabling application is backhauling wireless APs, how much speed is enough to support your wireless users? Finding the answer is tricky because you’re answering for both the users of today and tomorrow.
- Maximum distance is less important than it might seem because network cabling plants work within a radius. Network closets are placed strategically throughout a building, each closet at the center of a connectivity circle. Don’t rule out CAT 8 because it doesn’t reach as far as CAT 6. Your school is unlikely to require 100-meter runs everywhere.
- Longevity is the trickiest variable to factor into a wiring decision. A cabling plant will be in place for a decade or more. Today’s more expensive CAT 8 installation might save the district money tomorrow.
When it is time to upgrade, work with a professional cable installer to determine your cabling plant’s capabilities and the right cable for your school.
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