I am trying to identify what the purpose of this was, and whether it is safe to cut this cable. This Verizon Fiber ONT (optical network terminal) has a blue and white cable coming from this interface:

enter image description here

It is running up and over to this old copper phone line (Bell Atlantic) panel which appears to be capped off.

(front): enter image description here

(inside): enter image description here

There are however some wires that are running from this phone interface to a tube on the right and under my basement window: enter image description here

I have a lot of Cat5e in the house that terminated in the basement next to this BA panel here: enter image description here

I want to re-purpose the Cat5e which is terminated throughout the house as RJ11, and use it as RJ45 and hook it up to get 1Gbps internet. I am trying to determine what at one time was coming out of this ONT:

What is the blue and white Cat3 cable going to the Bell Atlantic box that is now capped off?

What is the brown and white cable next to that that is capped off?

What is currently hooked up to this interface panel that's going underground?

  • The blue and white wire is NOT "capped off" - it's spliced to the blue and white pair of the OTHER customer side cable in that abandoned Bell Atlantic interface box, so it will (or can) provide POTS on the blue/white pair to wherever the POTS used to provide service to on that cable.Indeed, at that end, the Orange/White pairs are also spliced as for two-line service. Can't see if the orange/white are connected or not at the ONT end.
    – Ecnerwal
    Nov 20, 2020 at 14:28
  • Thanks @Ecnerwal! The orange/white pair is going over to the patch panel on the left, I haven't unscrewed it from the wall yet.
    – Kahn
    Nov 20, 2020 at 15:16
  • Problem is, I don't follow what here I can cut. I don't want or need land lines in any way.
    – Kahn
    Nov 20, 2020 at 15:22

2 Answers 2


When Verizon (which is the latest iteration of C&P Telephone -> Bell Atlantic) puts in FIOS, they convert the phone lines to run on the fiber from the central office and they come out of the ONT as copper which they then connect to the original Network Interface (a.k.a. DMARC). ("Network" refers to "telephone network", not to Ethernet.) That network interface will have wires going to the rest of the house and also often still have wires going back out to the street. At some point (typically in or very close to the network interface, they will disconnect the old lines in order to avoid problems.

Each phone line users 2 wires (the RJ11 jacks can handle 4 wires = 2 phone lines). You actually have space for 6 (possibly 12, not clear if that is 6 repeated left & right or 12 separate lines), but currently you only have 1 line connected on the blue/white pair. Blue/white is one of the standard colors within a 4-pair cable, but is also standard for "cross connect" wires, which is the actual function here.

Do you have any traditional "land lines"? Do you want to have any "land lines"? Or are you in cell phone and/or VOIP mode? If you have no need for regular land lines (aka POTS) then you can ignore the old network interface. If you do want regular land lines then there are a number of different ways of wiring them, some of which will make use of that network interface, but not all.

  • Thanks - here is a photo of one of the terminations in the rooms: imgur.com/eZHIpTe it looks like 3 pairs are in the jack and 1 is wound around due to be excess. I don't think this is rj11, but rather...rj25?
    – Kahn
    Nov 20, 2020 at 0:08
  • 1
    Rj12. I used those a lot for serial printers and terminals. Nov 20, 2020 at 0:12
  • 1
    Woo! I'm so glad to know this, it was actually driving me crazy. Although I don't fully understand the cable layout on the punchdown panel. Anyway, it all looks disconnected from the Bell Atlantic panel, so I'm going to cut these Cat5e cables and recrimp them for my switch/router. Then repanel the rooms with RJ45. I should be good.
    – Kahn
    Nov 20, 2020 at 0:19
  • 1
    Don't crimp connectors on. Use CAT 5e (or similar) punchdown panel and/or RJ45 jacks. They are much more reliable than crimping connectors on and patch cables (i.e., factory made cables with connectors) are dirt cheap and easily replaced when they break. Nov 20, 2020 at 0:32
  • are you recommending punching down to the existing block, then punching in patch cables to the patch panel, instead of just putting end on the existing cables and running them directly to a patch panel?
    – FreeMan
    Nov 20, 2020 at 14:01

To start, let's talk about what this equipment is.

The Verizon ONT, pictured at https://imgur.com/gDu4Ltr, is the termination point of Verizon's optical network. This breaks out the fiber network into services that are more useful to the people at the service location; the internet, the phone line(s), and the cable TV service.

The telephone network interface pictured at https://imgur.com/DffmBzh is the termination point for the old Plain Old Telephone System (POTS) network that provided phone service to the location

The device pictured at https://imgur.com/kiiKv6U is a telephone breakout box, most likely used to direct incoming signals to multiple phones so that the phone could be answered from multiple rooms.

So, all that being said, the very first question you should ask is, "Do I own any of this equipment?" The answer is most likely not. Verizon, formerly Bell Atlantic, most likely owns all that equipment, down to the cables run through the walls. You should call them to verify who owns the equipment before proceeding.

If you do own at least the cables, that still may not mean it is viable to convert your existing RJ-11 jacks to RJ-45. Phone lines, and RJ-11 connectors, uses four lines, while Cat5e uses eight. So most likely the Cat5e cable is being terminated at two physically separate locations. If the entire cable is run through the junction box behind an RJ-11 plate it may be possible to re-terminate it as RJ-45 there, but the other jack will be dead.

You should verify how many twisted pairs are being run to each junction box after verifying you own the cables, if there are four twisted pairs it is possible to repurpose it for ethernet use.

  • The only cables the phone company owns or will take any responsibility for are the ones supplying service to the cutomer interface device. That is, in fact, the whole point of the customer interface device - "after this point it's your problem, not our problem." That includes cables the phone company may once have installed and owned, but CAT5e post-dts the point where phone companies got out of owning wires within your house to end-use points. With an ONT, leave the fiber the heck alone, the ONT is your customer interfce now.
    – Ecnerwal
    Nov 20, 2020 at 14:25

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