Over the years networking cables and the technologies they utilize have evolved tremendously, as network performance requirements have been pushing the envelope. From the 1950s, when the so called “Category 1” or CAT1 cabling was the de facto standard for voice to today where CAT8 cabling is currently being developed for super high speed throughputs, the technology of cabling has advanced exponentially. These category designations refer to Unshielded Twisted Pair or UTP cabling and the characteristics of their fabrication.
Although CAT2 to CAT4 cabling was used for low data-rate data communications, the biggest breakthrough for network communications came in 1991 with the standardisation of CAT5 UTP cabling. But what improvements does each category increment provide that allows for greater performance?
The main points of standardisation have to do with the performance characteristics of the cable. These include the frequency response, crosstalk limitations and allowed signal to noise ratios. These thresholds are achieved by standardising the physical characteristics of the cable which include the grade of copper, the diameter of the wire, the insulation material and thickness and the number of twists per length of each pair. Installation methodologies are also part of the standardisation which include the colours of the insulation of the wires, the maximum length of cable runs, the connector types and wiring of those connectors. By retaining these physical characteristic, the performance characteristics of the cable can be ensured.
These characteristics of CAT5 cabling allowed for frequencies up to 100MHz to be transmitted over the wires. This, in conjunction with Ethernet technologies, allow for connections of 100Mbps and 1000Mbps over 100 meters of CAT5 cabling.
Further improvements to UTP cables within the framework of CAT6, CAT7 and the currently under development CAT8 standards include stricter crosstalk specifications, higher frequency response of up to 2 GHz and shielding of individual pairs that will improve performance. CAT7 was developed in order to allow for 10Gbps Ethernet speeds over 100 meters of copper cabling and CAT8 to allow for 40Gbps Ethernet speeds over 100 meters of copper cabling.
One of the most important design characteristics of these categories is that they are all backward compatible back to CAT5. This is because all cables use the same wiring, the same physically shaped connectors and the same number of wires.
It is also important to note that although these cables have been developed with Ethernet in mind, there are many other applications including video, HDMI extension, and even cable TV.