EMZETT.Cat Cable
In short: Network cables (twisted-pair cables) following standardised “category” classes (e.g. Cat5e, Cat6, Cat6a, Cat8), each allowing different maximum speeds and cable lengths.
In more detail: A higher category number fundamentally means better shielding and higher supported bandwidth — Cat5e, for example, is enough for gigabit Ethernet, while Cat6a/Cat8 are meant for 10-gigabit connections. Important: the speed actually achievable is always limited by the weakest link in the chain (cable, network card, switch).
In Depth
Construction and how it works
“Cat” stands for “category” and denotes an internationally standardised classification (per ANSI/TIA-568) for twisted-pair copper cables — four twisted pairs of wires in a shared jacket. The twisting itself is no accident: it makes electromagnetic interference on adjacent wire pairs largely cancel each other out (crosstalk), which is further improved with rising category class through tighter twisting and sometimes additional shielding per wire pair (common with Cat6a/Cat7/Cat8, labelled as “S/FTP” or “F/UTP”).
The category classes at a glance
Typical values: Cat5 (outdated) and Cat5e support gigabit Ethernet (1 Gbit/s) up to 100 metres, Cat6 manages 10 Gbit/s under good conditions over short distances (up to about 55 metres), Cat6a reliably guarantees 10 Gbit/s over the full 100 metres, Cat7 (widespread in Germany, but not officially standardised internationally by the TIA) offers additional shielding, and Cat8 is designed for very short distances (typically data centres, under 30 metres) with up to 40 Gbit/s. As the category rises, the supported frequency bandwidth (measured in MHz) also rises — from 100 MHz for Cat5e to 2000 MHz for Cat8.
The weakest link
Important in practice: a Cat8 cable brings no benefit if the network card, router or switch only support gigabit — the entire connection is always only as fast as its slowest link, which is why cables, network cards and active network components have to be considered together when upgrading. A common mistake in practice: buying an expensive Cat8 cable but continuing to use the existing gigabit router — the actual speed gain then stays at zero.
Connector type: RJ45
Cat cables are almost always fitted with RJ45 connectors — an eight-pin connector type that contacts the four wire pairs. All category classes use the same RJ45 connector, which is why you can’t tell from the connector alone which category a cable actually meets — the category is usually printed on the cable jacket itself.
Rigid vs. flexible: solid and stranded cables
Cat cables also come in two construction types: “solid” (a solid copper core per wire) for permanent in-wall wiring, since it offers better electrical properties over long distances but can break over time when bent, and “stranded” (several fine strands per wire) for flexible patch cables that are moved or replugged more often, but have slightly worse transmission values over short distances in return. Permanent in-wall wiring is therefore practically always done with solid cables, while the short patch cables between wall socket and end device are usually stranded.
When Cat6a/Cat8 are worth it
For most home users, Cat6 or Cat6a is more than sufficient, since internet connections rarely exceed 1 Gbit/s and the internal home network is also rarely equipped with more than gigabit devices. Cat8 cables are primarily intended for data centres and very short high-performance connections between servers, where 25- or 40-gigabit connections are needed over a few metres — in a home network, a Cat8 cable brings practically no measurable benefit over Cat6a, but causes unnecessarily higher costs.
See also: Cabling plan, Patch panel, Ethernet, Router, Switch, Bandwidth