Note that, as is typical for a single line install, you only have 2 wires active, and a 2 or 4 wire jack would work just fine as it's only the white-with-blue (going to green, old-style)/blue (going to red, old-style) pair that are doing anything, on the center two contacts of the jack. 4 contacts of a 6 wire jack are doing nothing.

You may want to disconnect (unplug) your line at the Network Interface (typically a gray box on the outside of the house with a telephone symbol, and a screw marked "customer access" keeping it closed) before rewiring, as there is some danger of shock if anyone happens to call while you are moving the wires. Ring voltages run about 90VAC.

Answer from Ecnerwal on Stack Exchange
Top answer
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9

Note that, as is typical for a single line install, you only have 2 wires active, and a 2 or 4 wire jack would work just fine as it's only the white-with-blue (going to green, old-style)/blue (going to red, old-style) pair that are doing anything, on the center two contacts of the jack. 4 contacts of a 6 wire jack are doing nothing.

You may want to disconnect (unplug) your line at the Network Interface (typically a gray box on the outside of the house with a telephone symbol, and a screw marked "customer access" keeping it closed) before rewiring, as there is some danger of shock if anyone happens to call while you are moving the wires. Ring voltages run about 90VAC.

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What you have there are punch-down connections, where the wire is forced into a slot that cuts through the insulation and makes the electrical connection.

To replace them with your new screw-terminal type jack:

  1. Pry the wire out of the slot.
  2. I would suggest that you cut off the part of the wire where you can see the insulation is nicked, because the metal will also be nicked and might be fragile there. This might not be necessary.
  3. Use a wire stripper to expose some bare wire.
  4. Hook the wire around the screw and tighten it down.

To keep the jack wired the same as before, make sure you pair your blue-with-white-stripes wire with the jack's red wire and the white-with-blue-stripes wire with the jack's green wire.

However, there is something weird here: the blue-with-white-stripes wire seems to be looped through the jack and on to a splice with the green wire. This is strange, because wires should always be paired and the white-with-blue-stripes wire isn't doing the same thing. But perhaps the other splice is joining 3 wires (I can't quite tell). In any case, make sure to preserve any wire joins, as they might be part of the wiring for another jack on this same phone line. You may wish to replace the loop with a new 3-way splice, or you can try cutting the loop and putting both ends of it under the red screw.

The exact way you make the connection doesn't matter too much, as long as everything has continuity that did before.

Discussions

Old Phone Jack and rewiring inside house - DoItYourself.com Community Forums
Communications: Voice, Radio, Data Transfer Products and Devices - Old Phone Jack and rewiring inside house - I replaced the vinyl plank flooring in my mom's old room (she passed away from dementia in late 2018) and saw an old phone jack with a 'new' telephone wire (gray-colored) plugged into ... More on doityourself.com
🌐 doityourself.com
January 8, 2022
Is it worth keeping old phone jacks for future home network wiring?
First you should just be honest with your wife and tell her that you don’t want to do it. Second if you think you are going to wire your house for a home network you should absolutely keep those in place. I was in exactly your position when I moved into my house. (Wanted to install a network later.) I pulled all my cat6 cable in my house by taping the cat6 to the old phone line cable. It was a breeze. That said I kept the coax cable in place and just replace the phone lines. You, of course, may want to do differently. Now I have multiple access points with the Cat6 doing the back haul. More on reddit.com
🌐 r/HomeNetworking
18
7
August 16, 2023
Old phone jack. Can I just cut the wiring and leave in the wall, then patch over?
If you're interested, that wiring is capable of handling data (your internet from router) if you ever wanted to have Ethernet ports in the house More on reddit.com
🌐 r/Renovations
19
19
February 21, 2022
Replacing phone jack questions - DoItYourself.com Community Forums
If you get a jack that's looks OK, and your phone plug fits it will probably be OK. On a regular phone the 2 middle pins is used and polarity is of no importance. (Older equipment may be sensitive to polarity) The black and yellow wires are for a line no 2 or light or ground on non regular phones. More on doityourself.com
🌐 doityourself.com
May 8, 2022
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The Spruce
thespruce.com › how-to-wire-a-telephone-jack-1152704
How To Install a Phone Jack
July 27, 2023 - The Spruce / Kevin Norris. Strip 2 to 3 inches of the outer sheathing from the phone cable, using wire strippers. An old-style four-wire cable can be stripped using the 10-gauge slot on the wire strippers.

Note that, as is typical for a single line install, you only have 2 wires active, and a 2 or 4 wire jack would work just fine as it's only the white-with-blue (going to green, old-style)/blue (going to red, old-style) pair that are doing anything, on the center two contacts of the jack. 4 contacts of a 6 wire jack are doing nothing.

You may want to disconnect (unplug) your line at the Network Interface (typically a gray box on the outside of the house with a telephone symbol, and a screw marked "customer access" keeping it closed) before rewiring, as there is some danger of shock if anyone happens to call while you are moving the wires. Ring voltages run about 90VAC.

Answer from Ecnerwal on Stack Exchange
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Wikihow
wikihow.com › computers and electronics › telephones › how to install or replace a residential telephone jack
How to Install or Replace a Residential Telephone Jack
February 19, 2026 - Twist the tips of the new wires with the tips of the old wires according to color: red to red, green to green, yellow to yellow, and black to black. Replace the twisted portions of the wires under the screws in the jack, and tighten the screws.
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Wikipedia
en.wikipedia.org › wiki › Telephone_jack_and_plug
Telephone jack and plug - Wikipedia
February 22, 2026 - The back of a US four-pronged telephone jack (1964) The installation of a conventional wired telephone set has four connection points, each of which may be hardwired, but more often use a plug and socket: telephone line to phone cord: The wall jack. This connection is the most standardized, ...
Find elsewhere
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Wallplate Warehouse
wallplatewarehouse.com › wallplate warehouse › phone jack wiring
Phone Jack Wiring
September 20, 2021 - Step 1 - Strip the Wires Strip about 2 inches of outer sheath from the cable. Be careful not to nick the internal paired wires as this will cause the wire to break or short out the connection causing problems down the road.
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Family Handyman
familyhandyman.com › home › house & components › systems › electrical system › wiring
How to Replace a Wall Phone Jack
August 28, 2019 - Remove the two screws on the jack faceplate and disconnect the old jack. Hold on to the wire when you remove the jack so it doesn’t slide out the back of the box.
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Reddit
reddit.com › r/homenetworking › is it worth keeping old phone jacks for future home network wiring?
r/HomeNetworking on Reddit: Is it worth keeping old phone jacks for future home network wiring?
August 16, 2023 -

My wife and I recently bought an old house (built around 1870). Most of the interior walls are plaster and lath. The house isn’t wired for Ethernet cable but it has been wired for a phone line, with jacks in many of the rooms. (Coax in one or two of the rooms as well.) since we don’t have a landline or use cable (we have a Fios for internet, currently over a mesh network), my wife would like me to cut the wires and patch the holes.

Someday in the future when I have a bit more cash I’d like to wire the house for a home network, but in terms of budget and priorities that’s not going to happen for a while, especially given how hard I expect it to be in such an old house. My question is if it’s worth keeping these phone jacks open (and just covering with a blank plate) for a hypothetical future network. I know the actual phone cables (which are old) would need to be replaced, so I suppose my question is if it would make fishing and installing the wires significantly easier/cheaper.

Mostly I just don’t want to go to the trouble of patching the walls and sometime down the road realize my life would be easier if I’d left the jacks in. Thanks for any advice !

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Engineer Fix
engineerfix.com › what-to-do-with-old-phone-jacks-and-wiring
What to Do With Old Phone Jacks and Wiring - Engineer Fix
December 30, 2025 - This conversion potential is entirely dependent on the type of cable installed. If the wiring is confirmed to be Cat5e or better, it contains eight separate conductors that can be correctly terminated with RJ-45 connectors for Ethernet use.
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Easy-do-it-yourself-home-improvements
easy-do-it-yourself-home-improvements.com › diy electrical › diy home telephone wiring
DIY Home Telephone Wiring
If you have a newer connecting box (I beleive they are called R66 Connecting Block or a 2 Pair Connecting Block) just find an empty pair of screws and connect the wires in. NOTE: Line 1 is usually the only telephone line you need to connect ...
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Reddit
reddit.com › r/renovations › old phone jack. can i just cut the wiring and leave in the wall, then patch over?
r/Renovations on Reddit: Old phone jack. Can I just cut the wiring and leave in the wall, then patch over?
February 21, 2022 - You can buy 1 piece plates which are Colour coded for wire placement. Just make sure to find the other side of this cable, too or obviously it’s not very useful. ... There’s also the option of getting a blank cover plate that you can install on the box. It will look clean and you won’t have to go through the hassle of cutting out the box and doing a drywall patch. ... Do you live in an area prone to lightning? I have a vivid memory of seeing blue sparks come out of an vacant phone jack when my childhood home was struck by lightning.
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Today's Homeowner
todayshomeowner.com › electrical › electrical projects & installations › how to install a phone jack
How to Install a Phone Jack (2026) | Today's Homeowner
The wires are color-coded — red and green for line one, yellow and black for line two, and blue and white for line three. After removing the wires from the old jack, attach them to the new one.
Published   April 9, 2025
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Mr. Electrician
mrelectrician.tv › home › telephone › telephone wiring color code
Telephone Wiring Color Code - Mr. Electrician
April 21, 2026 - The four-pair wire can have four separate telephone lines at each jack location. However, if you only have one phone line for your house, you should use the same color pair for each new phone jack you install.
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Family Handyman
familyhandyman.com › home › house & components › systems › electrical system › wiring
What to Do With Your Old Wall-Mounted Phone Jack | Family Handyman
February 14, 2025 - Once this is done, attend to the wires. Marotta recommends disconnecting the wires at the main phone box first if possible. Then, snip the wires and tape the ends with electrical tape before tucking them into the wall.
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Kyle Switch Plates
kyleswitchplates.com › home › help › help guides & ideas › painting switch plates: how to a paint wall plate for best results › telephone jack installation instructions
Telephone Jack Installation Instructions & Photo Guide
Modular Jack to be installed: Front ... jacks. Inside of the old phone plate we are replacing. There is one set of wires (one solid blue, the other white with blue stripe) that is attached to the old plate....
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Build My Own Cabin
buildmyowncabin.com › electrical › phone-wiring.html
Phone-wiring
Here are the different types of phone jacks you might see: ... Second, you can buy modular jacks either with or without the wiring block (this is the heavy plastic piece which you mount to the wall, with screws to attach the wires to; see the picture higher up on the page). If you're installing a totally new jack, then you need the wiring block. If you're upgrading an existing, old-fashioned (pre-modular) connection to a modular jack, you might be able to use the existing wiring block, in which case you don't need to buy the kind of jack with the wiring block included; sometimes you can take the old cover off and just put a new modular cover over the old wiring block.
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Tek-Tips
tek-tips.com › home › forums › hardware, data and voice › wiring closet › cabling
Can anyone help me identify this old phone cabling? | Tek-Tips
September 25, 2021 - For an Avaya Partner ACS 4 wire system, the wiring would be: White/orange -> ??? Black pin 5 ??? Blue -> pin 2 - Red White/Blue -> pin 1 - Green Orange -> ??? Yellow pin 6 ????? ... The first one is a 6p4c "RJ-11" I think Suttle or Reliance used to make them, haven't used them in a very long time. Good for solid conductors. The second is a standard USOC 8p8c "biscuit" jack, again usually made by Suttle or Reliance or other Western Electric clone.
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Phone-jack
phone-jack.org › us-old
US (Old) Phone Line and Phone Adapter - Phone Jack
Information guide to the old US phone line and phone adapter, including phone plug, phone cord, wireless phone jack, and phone wire.