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How to convert your home's old TV cable into powerful Ethernet lines

If you've cut the cord, you probably have yards of unused coaxial cable in your walls. We'll show you how to turn that dormant cabling into an integral part of your home network with just a couple of adapters.
Written by Michael Gariffo, Staff Writer
Reviewed by Alyson Windsor
A tangle of coaxial cables and adapters

Take a deep breath. It's not as scary as it looks...I promise.

Michael Gariffo/ZDNET

If you're not already familiar with it, coaxial cable (seen above) is that round, usually white, sorta stiff cable that once carried all forms of pay TV services, including cable and satellite-based subscriptions. The cabling was run throughout just about every home that ever had a pay TV or internet connection for several decades. 

But, as technology marched on, many of us moved away from these TV services in favor of streaming our TV and movies over the internet. For a time, this left many homes still using a single coaxial cable line to carry their broadband signal to a modem, but even those have largely been replaced by Ethernet due to many ISPs requiring its usage for service tiers over 100Mbps. 

Because of these transitions, millions of homes have seemingly useless coaxial cables and coaxial outlets emerging from walls and floors. But, don't rip all that cabling out just yet. With a couple of relatively inexpensive adapters, you can use those lines that already spiderweb across your home to carry the same data that would otherwise require hundreds of feet of expensive-to-install Ethernet cabling.

 Review: Slow internet at home? This adapter can turn your unused coaxial cable into Ethernet

In fact, one of these adapters can connect any two devices that use Ethernet connections – modems, routers, switches, PCs, security cameras, streaming devices, and more – even if they're on opposite sides of the house. Read on to find out how to turn that idle coaxial into a ready-to-go, whole-home networking asset. 

How to convert your home's coaxial cable into Ethernet lines

  • Materials needed: Built-in coaxial cabling, a coaxial-to-Ethernet adapter kit, any networking hardware you're hoping to connect
  • Estimated time: 30 minutes

  • Estimated cost: $115 to $150 (depending on adapter model)

1. Locate the coaxial cable line you want to adapt

The first, and often most difficult, step in this process is locating the coaxial cable line you want to adapt to Ethernet. Since most cable runs are within walls, it's hugely helpful if the cable is labeled at both endpoints. Unfortunately, that's not always the case.

This is a great time to have a friend or family member to help with this process while in voice contact via something like a walkie-talkie smartwatch app, or even just a phone call. If you have a bare coaxial line emerging from the wall, it may be as simple as having them jiggle one end while you watch the other for movement. Or, if you have a built-in outlet, it may take a little more detective work to visually verify which line is which. 

If you can't figure it out, the rest of the process is simple enough that you can just take your best guess and, if you've gotten it wrong, you can start over with your next best candidate for which line it is that's running to your desired endpoint. If you're short on time, there's a hugely helpful tool we cover in the FAQ section below that can speed things up.

A coaxial wall port

The termination will either look something like this (if it's a wall-mounted port), or like one of the many cables pictured at the top of the guide.

Getty Images

2. Connect your first adapter

Once you have your line of choice verified (or you've taken your best guess), the next step is to begin connecting the adapter kit you've purchased. We've included several adapter candidates below, and would suggest choosing whichever model best suits your goals for speed and security. 

To install the adapter, you'll need to make a total of three connections: 

  • Coaxial cable: will screw into the port marked G. Hn., In, or MoCa (Multimedia over Coax Alliance), depending on your model
  • Ethernet: will click into the Ethernet port
  • Power: should usually be connected last

The power adapter type will vary from manufacturer to manufacturer, but is almost always needed to provide the current used to convert and carry your Ethernet signal over coax.

Also: Did your TV streaming bill just go up again? Here's why I chose YouTube TV

Some adapters may also have a TV or Out port for a second coaxial cable. This is used if you still want the same cable to carry a TV signal. While it is possible to keep an active cable or other pay TV connection running over the same line, we'd recommend avoiding it, if possible. The two competing signals have the potential to interfere with each other, potentially leading to poor performance for both.

An Ethernet cable, coaxial cable, and barrel power plug on a green background

These are (left to right) the Ethernet cable, coaxial cable, and power cable we're connecting to our adapter.

Michael Gariffo/ZDNET

3. Connect your second adapter

This is the same as the previous step, just performed again at the other end of your chosen coaxial cable run. 

The placement of each adapter depends entirely on your goals for this new coax-to-Ethernet run. For example, if you're attempting to connect your incoming broadband connection to a modem or router that will be located elsewhere in your home, you'll want one adapter wherever the broadband connection enters your home, and the other located wherever you want your router, with a coaxial line located between them. 

Likewise if you want a hardwired connection running from an existing router to a basement home theater setup for reliable 4K (or even 8K) streaming, you'd place one adapter near the router and the other near your home theater. 

Think of these adapters as endpoints for a run of Ethernet. With their help, that's exactly what any old run of coaxial cable can become.

An Ethernet to coaxial adapter with 3 cables connected

Your adapter should look something like this when fully connected. That empty coaxial port is there if you still want to connect a pay TV service over the same cable run, which we don't recommend.

Michael Gariffo/ZDNET

4. Connect all of your other networking hardware

Once you've got your adapters up and running, the final step is to connect any network hardware you want joined by your newly created line. This can include anything like the examples in Step 3, as well as other streaming devices, network switches, PCs, wireless network extenders, cameras, and similar tech. Again, anything that could normally connect via Ethernet is a candidate.

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Once you've connected your other networking hardware and verified the connection is up and running, you should be good to go with your new home networking setup. 

You can also repeat this entire process to convert other runs of coaxial cable to Ethernet, but you'll need another set of adapters for each.

The back of a networking device with two Ethernet cables plugged in

Once your adapter setup is complete, you can connect your streaming devices, additional networking hardware, PCs, and other devices.



Which adapter should I buy?

This depends entirely on your goals for the run, the level of security you want, and other factors specific to your home and devices. However, we've collected a few good candidates for the most common scenarios below. 

This is the adapter we used in our demonstration. It includes built-in encryption for security, and offers maximum speeds of up to 2Gbps. Read our full review of the Nexuslink G.hn Ethernet Over Coax Adapter here

A starter kit that supports MoCa 2.5 for running entire home networks over a single coaxial cable. A great option for those upgrading to a faster broadband tier that might otherwise require Ethernet installation.

A cheaper alternative to the above model that offers very similar features but comes with a few less cables and adapters that you may need to provide yourself, depending on your situation. 

Can I use this method to connect my entire home to my ISP? 

Yes. One of the main reasons why adapters like these are most commonly used is to help customers upgrading from slower (100Mbps or so) broadband connections to something faster (300Mbps or more). Since many broadband connections above 100Mbps require Ethernet cabling to be run from their origination point to a modem or router, lots of customers were stuck with a huge bill to replace their existing coaxial connections (which were fine up to 100Mbps) with the required run of Ethernet. Instead, these adapters offer a way to convert that existing coax into Ethernet at both ends, letting you connect broadband hardware, even hardware running at up to 1Gbps, to a modem or router over your existing coaxial cable.

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If you're planning to do this, I recommend choosing an adapter kit that uses the "bonded MoCa 2.5" protocol. This is a standard created by the Multimedia over Coax Alliance (MoCa). It's rated for up to 2,500Mbps (2.5Gbps), and was designed to carry the kind of traffic an entire network is likely to create. Other adapters may work, but you could experience some slowdown based on what specific protocols and technologies they support. Obviously, you don't want to pay for gigabit broadband only to be accidentally throttling yourself to less than 300Mbps by using the wrong hardware.

What if I'm having trouble figuring out which coaxial line is which? 

In homes that had lots of TV all hooked up to cable or satellite hardware at one point, you could be dealing with dozens of lines of coax running through walls. If you're not lucky enough to have them helpfully labeled for you, it may seem too daunting to trace each run. Thankfully there is a very helpful tool that can expedite the process. 

This inexpensive gadget lets you plug one end of it into a run of coaxial cable, go to the other end, and screw on a tiny speaker. If you hear a tone, you've found a complete run. If not, you need to try another endpoint. It's a huge help if you have in-wall coax outlets that prevent the "jiggle it" method, or if you don't have any help handy to sit at the other end. I'd recommend picking one up if you're serious about making use of your home's defunct coax for more than one run.

What are some other uses for converting coaxial cable into Ethernet? 

As mentioned above, essentially anything that could be handled by a run of Ethernet could also be done by a coaxial cable with the appropriate adapters at either end. But, just to set you on the path to how varied those possibilities are, we'll include a handful of other example scenarios below. You could...

  • Use a run of coaxial cable to create a hardwired connection to a Wi-Fi extender to counteract a Wi-Fi dead zone in your home or office.
  • Connect a gaming PC over adapted coax to reduce the game-breaking latency Wi-Fi can sometimes introduce.
  • Hardwire a security camera to eliminate any chance of missing an important moment due to flaky Wi-Fi. 
  • Create a fast, wired connection between a NAS (Network Accessible Storage) device and a remote computer or media streaming setup.
  • Install an over-the-air broadcast antenna and receiver that you'll use with adapted coaxial cable to connect to your LAN for streaming or recording.
  • Or just skip the hundreds or thousands of dollars a contractor might charge to install any in-wall runs of Ethernet cabling for any other purpose.
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