▷ RJ45 Ethernet cables: all types, categories and maximum speed

cat 6 ethernet cable

Despite the fact that WiFi networks are gradually replacing traditional Ethernet cables (better known as RJ45, RJ-45 or RJ 45 cables), the truth is that currently it is still the best measure to enjoy 100% of the connection hired. Internet speed is one of the most important aspects when opting for a cable of this type over wireless connections. Currently there is a wide variety of categories of Ethernet cables (category 5, 5e, 6, 6a, 7…) , and the basic difference between all goes beyond the age of the protocol.

Something that we must take into account before buying a certain category of RJ 45 Ethernet cable is the maximum speed that our network adapter supports as standard. Generally we can see it in the computer case or by searching for the model in Google.

Differences between Category 5, 6, 7 and 8 Ethernet cables

rj45 cable

In 2019 there are seven categories of Ethernet cables that we find in the market. Specifically, we can find the following:

  • Ethernet Cat 5
  • Cat 5e Ethernet
  • Ethernet Cat 6
  • Cat 6a Ethernet
  • Ethernet Cat 7
  • Cat 7a Ethernet
  • Ethernet Cat 8

Although each category corresponds to a cable generation, the truth is that the differences between them are based on factors such as the maximum transfer speed (download speed and upload speed), the working frequency and the twisting of the cables. .


Speed ​​is one of the most important aspects when deciding on a certain type of cable. Today the TIA / EIA-568-B (Association of Electronic Industries and Association of the Telecommunications Industry) is the body in charge of establishing a specific speed for each type of Ethernet cable.

In general, each new generation of cable introduces improvements in the maximum supported speed , although this is not always the case.

gigabit ethernet cable

The maximum speed supported by the router or the network card is usually defined on the back of the device in question. In this case, the maximum speed is 1,000 Mbps, or what is the same, 125 MB / s.

It should be added that even though the standard defines a speed for a given protocol (Cat 5, Cat 6, Cat 6a ...), it is likely that we will not reach the maximum range speed due to factors such as cable quality, cable length of the same or the specifications of the network card of the router and the computer .


The frequency, in addition to defining the power of the wired network, largely establishes the range of data loss along the cable and the width of the cable .

ethernet cable category

And it is well known that the longer the cable, the higher the rate of speed loss. Following the same logic, the higher the frequency, the lower the loss ratio the longer the length. Therefore, the longer the cable length, the lower the transfer speed even if the standard indicates a certain figure.

Braiding of threads

But the differences between protocols are not limited to speed and frequency. Generally, the advance between generations usually brings a series of improvements related to the braiding of copper wires and their shielding inside the cables.

Ethernet cable

Inside the plastic capsule the type of yarn braiding can be observed.

This is especially useful to reduce interference and therefore the range of loss when transmitting information.

Cat 5 Ethernet Cable

This category is not only the oldest, but also the most basic. So much so that it is not recognized by the TIA / EIA-568-B given its age and low specifications.

Cables based on this category have the following characteristics:

  • Maximum speed : 100 Mbps (15.5 MB / s download)
  • Maximum frequency : 100 MHz

Cat 5e Ethernet Cable

We enter the field of Gigabit connections. The evolution of category 5, this time recognized by the aforementioned regulatory bodies, is the most common today in most Ethernet connections as it is a fairly cheap standard to implement.

Regarding their characteristics, category 5e cables have the following specifications:

  • Maximum speed : 1,000 Mbps (150.5 MB / s download)
  • Maximum frequency : 100 MHz

Cat 6 Ethernet Cable

Little by little, Category 6 Ethernet cables are replacing the old ones. Today it is used in Fast Ethernet networks that require a stable connection to have a higher frequency.

Its characteristics are defined by the following specifications:

  • Maximum speed : 1,000 Mbps (150.5 MB / s download)
  • Maximum frequency : 250 MHz

Cat 6a Ethernet Cable

The middle step between category 6 and 7 cables. We make way for 10 Gigabit networks , with up to ten times the speed of previous standards and a frequency that exceeds twice that of category 6 cable.

With a 10 Gigabit network, few are the routers and network cards that are compatible with this type of cables . That is why we will have to be careful when choosing one cable or another.

The characteristics of Cat 6a Ethernet are as follows:

  • Maximum speed : 10,000 Mbps (1,250 MB / s or 1.25 GB / s download)
  • Maximum frequency : 500 MHz

Cat 7 Ethernet Cable

We change generation and continue with 10 Gigabit Fast Ethernet networks . In this case, the standard is certified under the ISO-11801 standard to operate internationally throughout the world more frequently than the previous categories.

Its specifications consist of the following characteristics:

  • Maximum speed : 10,000 Mbps (1,250 MB / s download)
  • Maximum frequency : 600 MHz

Cat 7a Ethernet Cable

We maintain transfer speed and improve the maximum frequency . One of the less frequent today due to its high cost of implementation.

Regarding its technical characteristics, the current standard leaves us with the following specifications:

  • Maximum speed : 10,000 Mbps (1,250 MB / s or 1.25 GB / s download)
  • Maximum frequency : 1,000 MHz (1 GHz)

Cat 8 Ethernet Cable

We come to the end of the list. Category 8 cable is currently the fastest, with a maximum speed similar to that of current USB Type-C cables that run under the Thunderbolt 3 standard.

With this new generation we say goodbye to the 10 Gigabit network and we get the 40 Gigabit network . Yes, you read correctly. Currently it is the most expensive to implement, but it is the one that offers the highest speed and frequency in spaces with wired networks.

  • Maximum speed : 40,000 Mbps (5,000 MB / s or 5 GB / s download)
  • Maximum frequency : 2,000 MHz (2 GHz)