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I moved into a new house which looks to be wired for sound, co-ax, and then telephone/Ethernet(?).

The coax and Ethernet lines all terminate to a single location that had an old tecgate server but nothing was connected. My question is how can I tell which lines are for Ethernet vs wired for telephones. Looks to be way move wires coming in here then there are jacks in the house and all wall jacks have Ethernet size plug in, but some only have 4 wires and not the full 8 for Ethernet so I am guessing that telephone? The only wires I have been able to trace are the two green wires, one in for internet coming into the house and one is for Ethernet going to an upstairs office that I am able to get internet to.

Trying to compress pictures to add them, sorry.

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  • The full 8 wires is most likely ethernet, but you'll need the know the type of cable (e.g. cat5e) to know how useful it is for home networking. If they aren't being maintained inside their twisted pair cable chances are poorer.
    – blarg
    Commented Jan 5, 2023 at 21:20
  • I added pictures. It looks like all the wires are 8 full put then are split into 4 wires per cap (not sure the word for the ethernet male end). Can these all be redone to ethernet caps on each end and they will function line normal ethernet? I believe most are cat5. The house was built in 1998.
    – Sean
    Commented Jan 5, 2023 at 21:31
  • 3
    They probably used 8-wire cable for both phone and network, and you can punch any cable down to any purpose. Commented Jan 5, 2023 at 22:06
  • 3
    The installer helpfully labelled at least some of those cables. You might find matching labels if you look at the wiring behind each outlet.
    – brhans
    Commented Jan 5, 2023 at 22:25
  • 3
    You need a cable tester: Get the kind that has 2 parts: one (sender?) that goes into a jack and then you go to the LV panel and see which cable is sending. There are tons of them out there with widely varying price ranges....since product recommendations are OT here, you'll need to do your own research, don't buy the cheapest, $8 one from Amazon, but you could be able to find a very capable unit for the $50-75 range. It'll save you a TON OF TIME. Commented Jan 5, 2023 at 22:52

2 Answers 2


It is super common to use Cat5 or Cat5e for telephone wiring, and that looks like what was done here. The problem with trying to reuse phone wiring for network wiring is that the phone system allows "daisy chaining" where one wire run serves multiple wall receptacles, whereas networking requires "home runs" where each receptacle has its own wire all the way back to the origin (usually a switch, router or patch panel).

For your situation, you can check whether you can convert to network wiring by opening up some of the wall receptacles and see whether your phone jacks have a single connection (good, likely goes back to this panel in your photos) or have wiring coming into the receptacle and going back into the wall to another receptacle down the line (bad, will require rewiring at least part of your home).

If you have Cat5/5e home runs already, you can re-terminate both ends with new punchdown jacks (preferred) or RJ-45 (acceptable) and then use network cable testers to validate that the cables and terminations are suitable for networking. Then you plug in a switch at the panel end and a computer/game console/tv/whatever at the receptacle end and you're set.

If you discover daisy-chains though, you could use the first receptacle in each chain and disconnect all the others down the line; but likely your best bet is to re-wire all receptacles at that point. You may be able to use the existing wires to pull new wires through, but it's just as likely they're stapled or otherwise constricted and not pullable.

  • if they are daisy chained you can use switches in every location where you want the connection to continue on. Commented Jan 6, 2023 at 2:06

A few basic notes:

  • You technically only need 4 wires for basic Ethernet. That actually allows you to run Ethernet and a phone, or two separate Ethernet connections. However, the normal setup for a very long time has been to connect all 8 wires (4 pairs), and that allows for anything, including Gigabit Ethernet, Power over Ethernet, etc.
  • Never, ever, ever crimp connectors onto the end of Ethernet cables! It is hard to well, even with the right tools. Manufactured patch cables are dirt cheap and can be replaced if a plug goes bad. Jacks hardly ever go bad. The usual setup if you have a lot of cables to connect is to install a patch panel such as this example from Amazon:

12 port patch panel

and then you use short network cables (a.k.a., Patch Cables) to go from the patch panel to your switch or router. On the other hand, you connect the cables to individual jacks in faceplates or use surface-mount jacks, depending on your setup.

  • Tools are key. There are two types of tools that will help you - diagnostic and installation. For diagnostics, you should get a toner/tester and a cable tester. The toner tester has two parts. You plug one part into a jack (or attach with clips to individual wires) and it generates a tone on the wire. You use the other part to scan different places where you think the same wire may be. It works "nearby" so you don't have to actually touch the cable to find it. A cable tester has a part you plug into one jack that somehow lets the other part check whether each wire is connected properly or not and display the results. There are some big names, with big costs - e.g., Klein and Fluke. (Though not nearly as expensive as they used to be - my first STM-8 cost around $ 300 around 30 years ago - apparently still available, now for $ 400 - can't believe anyone is actually paying that when you can get an up-to-date more powerful name-brand device for $ 60 or less. But that STM-8 was worth every penny. But I digress.) For a one-time job like this I'd pick up something inexpensive.

  • Last, but not least are installation tools. The most important thing is a punch tool like this Trendnet from Amazon:

Trendnet punch tool

You use a punch tool to attach the cables to the patch panel and to the individual RJ45 jacks.

  • 3
    I've probably crimped 400-500 RJ45 connectors in the last 20 years. I know that makes me a novice compared to most, but I had maybe 2 failures over that time. The key is to patiently straighten the wires.
    – RetiredATC
    Commented Jan 6, 2023 at 2:15

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