Not all Ethernet cable is created equally. What’s the difference, and how do you know which you should use? Let’s look at the technical and physical differences in Ethernet cable categories to help us decide.
Ethernet cables are grouped into sequentially numbered categories (“cat”) based on different specifications; sometimes the category is updated with further clarification or testing standards (e.g. 5e, 6a). These categories are how we can easily know what type of cable we need for a specific application. Manufacturers are required to adhere to the standards, which makes our lives easier.
What are the differences between the categories and how can you know when to use unshielded, shielded, stranded, or solid cable? Keep reading for “cat”-like enlightenment.
The differences in cable specifications is not as easy to see as physical changes; so let’s look at what each category does and does not support. Below is a chart for reference when picking cable for your application based on the standards for that category.
Cable twisting length is not standardized, but typically there are 1.5-2 twists per cm in Cat-5(e) and 2+ twists per cm in Cat-6. Within a single cable, each colored pair will also have different twist lengths based on prime numbers so that no two twists ever align. The amount of twists per pair is usually unique for each cable manufacturer. As you can see in the above picture, no two pairs have the same amount of twists per inch.
Many Cat-6 cables also include a nylon spline which helps eliminate crosstalk. Although the spline is not required in Cat-5 cable, some manufactures include it anyway. In Cat-6 cable, the spline is not required either as long as the cable tests according to the standard. In the picture above, the Cat-5e cable is the only one with a spline.
While the nylon spline helps reduce crosstalk in the wire, the thicker sheath protects against near end crosstalk (NEXT) and alien crosstalk (AXT) which both occur more often as the frequency (Mhz) increases. In this picture the Cat-5e cable has the thinnest sheath, but it also was the only one with the nylon spline.
Shielded (STP) vs. Unshielded (UTP)
Because all Ethernet cables are twisted, manufactures use shielding to further protect the cable from interference. Unshielded twisted pair can easily be used for cables between your computer and the wall, but you will want to use shielded cable for areas with high interference and running cables outdoors or inside walls.
Solid vs. Stranded
Solid and stranded Ethernet cables refer to the actual copper conductor in the pairs. Solid cable uses a single piece of copper for the electrical conductor while stranded uses a series of copper cables twisted together. There are many different applications for each type of conductor, but there are two main applications for each type you should know about.
Stranded cable is more flexible and should be used at your desk or anywhere you may be moving the cable around often.
Solid cable is not as flexible but it is also more durable which makes it ideal for permanent installations as well as outdoor and in walls.