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You’ve probably heard that using an Ethernet coupler can reduce your network speed, but is it true?

Ethernet couplers don’t lower speed. They can cause more defective packets if the cable length is around 100 meters. An increase in defective packets reduces throughput because of packet re-transmission, but speed remains the same. Too many errors can cause the Ethernet adapters to drop in speed.

ethernet coupler

What Is an Ethernet Coupler? 

In the most basic terms, an Ethernet coupler is a device that joins two Ethernet cables. It is designed as a rectangular plastic or metal box, with open ends where you enter the tail ends of the Ethernet cables. 

Inside the Ethernet coupler, the wires are marked with color codes similar to those on the Ethernet cables so that you can connect them easily and correctly. On the other hand, Ethernet cables have the connecting wires covered in a clear plastic sheath so you can see their colors. 

If the connection is made correctly, the wires in the Ethernet cable make contact with those in the Ethernet Coupler, and a connection is made. The notch inside the coupler secures the cable so that the connection continues undisrupted. 

There’s a vast selection of Ethernet couplers in the market today. They are categorized according to their corresponding Ethernet cables.  You’ll find the Ethernet cables are in four categories. These categories include Cat 5, Cat 5e, Cat 6 & Cat 6a. 

When you want to buy an Ethernet coupler, it’s important first to check the category of your Ethernet cable and buy an Ethernet coupler with a corresponding rating. This ensures that the wires rhyme and the connection are solid. 

How Does It Work?

First, you’ll need to get a matching Ethernet coupler depending on the Ethernet cables you’re using. It’s a cheap device, and you can get it easily in most electronics shops. 

Extend your Ethernet cable to its maximum length and then plug its tail end into the coupler. Pick up the next cable and plug its back into the opposite side of the coupler to establish a connection between the two cables. You can now plug the second cable into the computer and continue with data transmission. 

The wires inside the Ethernet coupler connect with the wires in the Ethernet cables so that it forms a continuation of the data transfer. If both Ethernet cables are plugged in correctly, there should be no problem with the transfer. 

Do Ethernet Couplers Reduce Speed?

Ethernet couplers are designed in a way that maintains the speed of the Ethernet cables as it is. They do not lower the speed. This is because the Ethernet couplers are designed to match their type of Ethernet cables for good connectivity. 

However, if you connect an Ethernet coupler and notice that the speeds went down, there must be a problem or different factors affecting it. 

Let’s look at some of the factors that may contribute to low speed when using an Ethernet coupler and how to deal with them. 

  1. Electromagnetic Interference (EMI)

The EMI in an environment is increased when there is a constant use of equipment like microwaves, generators, air conditioners, etc. Suppose you use an Ethernet coupler in such an environment. In that case, there’s a likelihood that the data transfer speeds will reduce, the data will be of low quality, and there will be a significant amount of errors in the data. 

The solution to this is to ensure that you buy an Ethernet coupler that is well shielded using high-quality shielding material. In the market, there are both shielded and unshielded Ethernet coupler options. You can notice the shielding material on the shielded couplers. For example, both cat 5 and cat 6 shielded options have a thin foil all around, which effectively blocks EMI. 

  1. Ethernet cable type vs. Ethernet coupler type

As mentioned earlier, it’s important to consider the type of Ethernet cable you’re using before getting an Ethernet coupler to go with it. Manufacturers recommend that you choose the same category for both Ethernet cables and Ethernet couplers so that you can have the best experience. 

In most cases, if you connect an Ethernet cable to an Ethernet coupler of a different category, you’re likely to experience signal failure and data loss. For those that connect successfully, they are likely to experience slow speeds due to the difference in specifications. 

Some models of cat 5e and cat 6 can connect with each other as with their advanced backward connectivity. If you’re looking to mix the models and connect a cat 5e to a cat 6, be sure to check whether they go well together so that you don’t affect the speed of data transmission. 

  1. Connectivity range

The different categories of Ethernet cables have a limit to the distance they can maintain high speeds of data transmission. It’s common for electrical signals or data transmissions to degrade as the distance increases between the connected devices. 

For example, if you choose to use a category 6 Ethernet cable, it is expected to maintain perfect speed and quality over a 328 feet distance in an ideal environment. However, different factors reduce this distance to about 180 feet of perfect connectivity.  That means, as long as the coupler is positioned within this range, the speed will not be interrupted. 

When buying an Ethernet coupler, be sure to check the specifications and compare them to those of the Ethernet cables you’re using so that you connect them within the recommended range.

  1. Quality of the Ethernet Coupler

It’s a rule of life that there’s a substandard matching item out there whenever there is an original high-quality product. So you have to be very careful when purchasing an Ethernet coupler and always ensure that you get the original high-quality one. 

Low-quality couplers are made of low-standard material, which could affect the connectivity between the two Ethernet cables. This will, in turn, affect the speed of data transmission between the devices. A high-quality Ethernet coupler ensures good connectivity, thus maintaining the data transmission speeds in the two Ethernet cables. 

ethernet coupler2

Are Ethernet Couplers Bad?

Suppose you’re working in one room, but you need to make a connection with another device in the next room. In this case, you’ll need a long Ethernet cable to do so. When your Ethernet cable is not long enough, you’ll need to use an Ethernet coupler to join another cable and extend the first cable. 

Ethernet couplers are advantageous because they help extend Ethernet cables when a connection is to be made between two distant devices. Also, you can use the Ethernet couplers to extend an Ethernet cable connecting to an internet router for good internet connectivity.

However, the points of contact between the Ethernet couplers and Ethernet cables could be a point of poor connection which can degrade the internet signal or data transmission speeds. It’s important to understand that an Ethernet coupler is an external device that is introduced into the data transmission or internet signal path. 

Therefore, every time you introduce an Ethernet coupler, you risk interference with the data transmission speeds and internet signals due to poor connection at the coupler.  

Another important thing to look at is the quality of the coupler. As mentioned earlier, a low-quality Ethernet coupler can frustrate your efforts of data transmission as it will lower the speed or even distort the data. Worse still, it can lead to significant data loss. 

To ensure you get the best results with your Ethernet coupler, it’s important to get high-quality shielded couplers for your connections. 


Ethernet couplers are a solution, especially when the connectivity is needed over a long distance, even though they risk poor connectivity or lower speed. It would be better to use a fairly long cable that can serve you without using a coupler and use a coupler only when necessary.