What Is Category in Network Cables?
Category, commonly abbreviated as CAT, is a classification system for the performance of twisted-pair network cables. Category defines technical requirements related to signal transmission capability, bandwidth, crosstalk, and support for corresponding Ethernet applications.
Some common Categories today include CAT 5e, CAT 6, and CAT 6A. Each category has different performance requirements.
| Category |
Nominal Bandwidth |
Common Ethernet Applications |
| CAT 5e |
100 MHz |
Gigabit Ethernet (1 Gbps) |
| CAT 6 |
250 MHz |
Gigabit Ethernet; can support 10GbE at suitable distances |
| CAT 6A |
500 MHz |
10 Gigabit Ethernet up to 100 m in compliant systems |
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Therefore, when a product is labeled CAT6, this primarily indicates that the cable belongs to Category 6. It does not indicate whether the cable has a shielding layer.
Similarly, CAT6A does not mean that the cable is shielded. CAT6A cables can be available in different shielding configurations, including both unshielded and shielded designs.
Another important point is that Category is not only related to speed. Category standards specify requirements for various transmission parameters, including insertion loss, return loss, NEXT, FEXT, and other crosstalk-related characteristics. Therefore, cable quality should not be evaluated solely based on the advertised network speed.
What Is Shielding in Network Cables?
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Shielding is a protective structure made from conductive materials, typically using foil or a metal braid, designed to reduce the impact of electromagnetic interference (EMI) on signals transmitted through the cable and to reduce interference between individual pairs or neighboring cables.
Shielding is not a Category. Instead, it describes how the cable is constructed and shielded. Therefore, both CAT6 and CAT6A cables can use different shielding configurations depending on the manufacturer's design.
To identify the shielding structure, users commonly encounter designations in the form of X/YTP. In this notation:
- U = Unshielded, with no shielding layer.
- F = Foil, using a foil layer as the shield.
- S = Braided Screen, using a braided metal screen.
- TP = Twisted Pairs, referring to the four twisted pairs inside the cable.
| Structure |
Overall Shield |
Individual Pair Shield |
Characteristics |
| U/UTP |
No |
No |
No metal shielding layer |
| F/UTP |
Foil |
No |
Foil surrounds all four twisted pairs |
| U/FTP |
No |
Foil |
Each twisted pair has its own foil layer |
| F/FTP |
Foil |
Foil |
Overall shield combined with individual pair shielding |
| S/FTP |
Braided screen |
Foil |
Overall braided shield combined with individual foil shielding |
For example, for a cable specified as CAT6A S/FTP:
- CAT6A indicates the Category level and transmission performance of the cable.
- S/FTP indicates that the cable has an overall braided shield and individual foil shielding around each twisted pair.
Therefore, simply seeing CAT6A is not enough to determine how well a cable can resist interference. To understand this, the Shielding specification must also be checked.
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U/UTP cables are generally suitable for environments with low levels of electromagnetic interference and offer advantages in terms of flexibility and ease of installation. Meanwhile, configurations such as F/UTP, U/FTP, or S/FTP can be considered when the system is installed in an environment with multiple sources of electromagnetic interference.
However, shielded cables only provide their intended performance when the entire system is installed using compatible components. Connectors, patch panels, keystone jacks, and other related components should also be compatible with the cable type. Installation and bonding/grounding must be performed according to the appropriate requirements. Therefore, users should not simply choose a shielded cable while overlooking the other components of the system.
How Should You Choose a Network Cable?
When selecting a network cable, it is useful to separate two questions: what level of transmission performance is required? and does the installation environment require shielding?
| Requirement |
Factors to Consider |
Reference Choice |
| Standard office or home network |
Speed and distance |
CAT 5e or CAT 6 |
| System requiring higher performance with a focus on 10GbE |
Bandwidth, distance, and system requirements |
CAT 6A |
| Environment with low electromagnetic interference |
Flexibility and installation method |
U/UTP may be suitable |
| Environment with significant EMI sources |
Interference level and shielding requirements |
F/UTP, U/FTP, F/FTP, or S/FTP |
| System requiring future upgrades |
Bandwidth and application requirements |
Consider CAT 6A |
It can be understood simply as:
Category = What performance level does the cable provide?
Shielding = How is the cable shielded and protected against interference?
These two factors complement each other rather than replacing one another. For example, CAT6 U/UTP and CAT6A S/FTP differ in both Category level and shielding structure. Therefore, when purchasing network cables, check the complete specifications instead of relying only on the CAT6 or CAT6A designation.
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In addition to Category and Shielding, determining whether a cable is suitable also requires consideration of the transmission distance, conductor diameter, conductor material, product standards, connector type, and installation conditions. A system must ensure compatibility among all interconnected components to achieve the desired performance.
Looking for the right network cable for your system? Hoàng Bảo Khoa provides network cables and connectivity accessories with various Category and shielding options. Contact Hoàng Bảo Khoa for advice on selecting the right cable based on your actual speed, distance, and installation environment.