How to Connect Ethernet Cables - Network Switches & Couplers

Learn how to connect Ethernet cables using switches and couplers.

TP-LINK TL-SG108 8-Port Desktop Switch Kevin Jones / TechReviewer

Last Updated: September 14, 2021

Written by Brandon Jones

In this guide, we discuss the different ways to connect Ethernet cables via Ethernet switches and Ethernet couplers.

If you want to learn more about cable internet equipment, wiring, or troubleshooting, check out these articles:

What Are Ethernet Switches?

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Ethernet switches, also called network switches, connect multiple devices via Ethernet cables (TR). Ethernet switches are different from routers. An Ethernet switch connects multiple devices within your local area network. In contrast, a router connects your local area network (LAN) to the internet's wide area network (WAN). Routers with multiple ports or Wi-Fi support are logically three separate devices: a router, a switch, and a Wi-Fi access point (TR).

Ethernet switches can connect multiple devices to a router via one Ethernet cable instead of each device needing a cable going to the router. Ethernet switches are helpful for when your devices are far away from a router, reducing the need for multiple long Ethernet cables.

Most types of Ethernet cables (TR) have a maximum distance of 100 meters. By using a switch, that distance can be extended.

How to Use Ethernet Switches

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You can add an Ethernet switch to your home network by following these steps:

  • Connect one end of an Ethernet cable to your router.
  • Connect the other end of that cable to an Ethernet switch port.
  • Connect another Ethernet cable to another Ethernet switch port.
  • Connect the other end of that cable to a device, such as a PC.

You will need to use the highest supported Ethernet cable between all devices to avoid limiting the network speed.

For example, suppose you use a Cat 5 Ethernet cable in one switch port but a Cat 6a Ethernet cable in another switch port. In that case, the slower Cat 5 cable will limit the max speed.

Many new Ethernet switches include "Auto MDI or MDIX." This feature lets you connect an Ethernet switch to other networking equipment using a standard (straight-through) Ethernet network cable. However, your Ethernet switch may not support this. In this case, you may need to use a crossover cable or crossover coupler for connecting two network devices (e.g., two switches).

What Is RJ45?

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RJ45 is the connector used for terminating most Ethernet cables, including Cat 5e and Cat 6a.

What Are RJ45 Ethernet Couplers?

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RJ45 Ethernet Couplers are used for connecting two Ethernet cables and are suitable for extending the span of an Ethernet cable. Ethernet couplers are cheaper than switches but are limited to only connecting two cables and cannot extend past the 100 meter limit of most Ethernet cable types (TR).

It's recommended to use a full-length Ethernet cable without any Ethernet Couplers whenever possible to reduce potential point of failures such as bad connection or interference.

How to Use an RJ45 Ethernet Coupler

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Connect an Ethernet cable into each end a RJ45 Ethernet Coupler. Then use the joined Ethernet cable as a regular Ethernet cable.

You will need to use your network equipment's highest supported Ethernet cables and respective couplers to avoid limiting the network speed.

For example, if you use a Cat 5 Ethernet cable on one side of the coupler but use a Cat 6a Ethernet cable on the other side, the slower Cat 5 cable will limit the max speed. The Ethernet coupler also needs to be rated for the same category as the Ethernet cable.

Ethernet Switch vs. Ethernet Coupler vs. Router

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  • Ethernet Switch: Connects multiple devices in your local area network (LAN) via Ethernet cables.
  • Ethernet Coupler: Joins two Ethernet cables.
  • Router: Connects your local area network (LAN) to the internet's wide area network (WAN). Routers with multiple ports or Wi-Fi support are logically three separate devices: a router, a switch, and a Wi-Fi access point (TR).

Cable Types

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Ethernet Cable Max Speeds and Distances
Cable CategoryMax Speed and Distance
Cat 5
  • 100 Mbps @ 100 meters
Cat 5e
  • 1 Gbps @ 100 meters
Cat 6
  • 10 Gbps @ 55 meters (37 meters if high cross talk)
  • 1 Gbps @ 100 meters
Cat 6a
  • 10 Gbps @ 100 meters
Cat 7
  • 100 Gbps @ 15 meters
  • 40 Gbps @ 50 meters
  • 10 Gbps @ 100 meters
Cat 8
  • 40 Gbps @ 30 meters
  • 10 Gbps @ 100 meters