49 votes
Accepted

How do I remove this wall plate with no visible screws?

It's not complicated, you just haven't used one before. I use ones like it all day long. The screws are hidden under the little rectangular plastic bits at top and bottom. Typically you push one end ...
Ecnerwal's user avatar
  • 214k
34 votes
Accepted

Mysterious cord running from wall. Safe?

That is a wired telephone junction block. The wire coming through the wall may very well be where the original land line entered the house from outside. The other wire is probably going off to some ...
Michael Karas's user avatar
  • 64.6k
25 votes

What is this in my wall?

This is a telephone jack. If you measure 48v DC or so between wires then it is live, even if you don't currently have phone service. Ideally - live or not - you should try and find the other end of ...
manassehkatz-Moving 2 Codidact's user avatar
22 votes
Accepted

What is this four connector-post, square electrical device mounted to my interior wall?

It's a beat up telephone jack. You can see the actual plastic jack off on the left, and there was originally a cover over the box.
Matthew Gauthier's user avatar
22 votes
Accepted

Mystery telephone wiring device in old house

Standard Bell System (Western Electric, usually) terminal block. Appears to be missing the protective devices, but those are not needed since it's no longer the NID. Sure, take it out and modernize if ...
Ecnerwal's user avatar
  • 214k
19 votes

Phone/cat3 equivalent of network switch

You are over thinking this. POTS (Plain Old Telephone Service) doesn't need a switch, a modem or a router. You just connect all the cat 3 (RJ11 jacks presumable) in parallel from one to the next. ...
George Anderson's user avatar
18 votes
Accepted

Old and unused power outlet

That is a junction box, and must remain accessible (plastic or metal cover, cover can be painted.) NEC 314.29 If the wiring is completely removed, you can remove the junction box, but usually the ...
Ecnerwal's user avatar
  • 214k
17 votes
Accepted

Testing phone installation without phone service

There are devices called "Tone Testers" which plug in to each end of a run and test the integrity of the wires. You should be able to pick one up for about $20. You can get them for RJ11 (...
gnicko's user avatar
  • 5,605
14 votes
Accepted

Phone line not working after jack removed

It is very common for phone lines to be installed in a daisy-chain manner. The wires might only be stripped a bit in the middle and continue on to the next jack. By cutting the wires at any point ...
Robert Chapin's user avatar
10 votes
Accepted

How do I update daisy-chained RJ11 to standard punch-down style keystone jack?

Don't punch more than one wire onto the new jacks. Your old jack had screw terminals that could also serve as splicers. Your new jacks do not, so just use something else inside the wall box to ...
jay613's user avatar
  • 37.8k
10 votes

Testing phone installation without phone service

If you're doing this a lot, a common tool is a Butt Phone amongst other things. This is capable of being a subscriber phone talking to the exchange (aka the Central Office), or the other way, ...
Criggie's user avatar
  • 10.6k
9 votes

Phone/cat3 equivalent of network switch

Waste of money, but feel free. A pair of wirenuts will do the job, unless you have more than one phone line coming in, and phones that understand more than one phone line on a single jack. In that ...
Ecnerwal's user avatar
  • 214k
8 votes

Phone/cat3 equivalent of network switch

Plain Old Telephone Service (POTS) doesn't use a switch like ethernet wiring. Telephone wires are all just connected together - red to red, green to green, etc. Usually it's installed in a daisy ...
Mark's user avatar
  • 3,773
8 votes

Mysterious wires running from wall - can I remove them

One is phone, the other is coax, most likely cable TV. Even if they are active, you can just chop them off with wire cutters. However, it is better to figure out where they are going and, more ...
manassehkatz-Moving 2 Codidact's user avatar
7 votes

Installed Electric Tankless Water Heater - Internet loss when active

First, make sure that your three supply cables are paired properly. The unit has 3 heaters internally. There are several ways cables could be crossed that would result in power from 1 heater coming ...
Harper - Reinstate Monica's user avatar
7 votes
Accepted

What is the purpose of power going into a Phone Receptacle?

From your back side picture it is apparent that no small gauge low voltage wiring goes to the box with the four prong plug. So unlikely that the plug was used for wired phone service at any time in ...
Michael Karas's user avatar
  • 64.6k
7 votes

Mysterious cord running from wall. Safe?

A few things to add to the other answer It was probably an older 4-pin jack that went there. This was the forerunner for the modern (and considerably more compact) RJ-11 jack you would recognize. ...
Machavity's user avatar
  • 24.8k
7 votes
Accepted

What kind of wiring/service are these wires for and how do I test them to find out?

They're almost certainly phone cables. Whether they're live or not is unclear from my chair. You can disconnect them one at a time and verify that you still have service. Phone and cable TV ...
isherwood's user avatar
  • 138k
7 votes

Why do phone and cables companies leave their cables behind, and what to do about it?

Now you've changed the question significantly to describe a wire fed from underground. Except you still have a trunk running down the pole, so this is still a wire coming down off a pole. Again, you ...
Harper - Reinstate Monica's user avatar
6 votes

Mysterious cord running from wall. Safe?

What you are looking at is a terminal block where a desktop telephone was once connected. The wire which disappears into the plaster wall runs downstairs to a larger terminal block where it is ...
David42's user avatar
  • 231
6 votes
Accepted

For phone jack, which terminals are used by modem?

You need to connect to the center two wires in RJ-11. Since RJ-11 is usually 6 pins, these are pins 3 and 4. If yours has only 4 pins, these should be pins 2 and 3. Leave the other pins unconnected. ...
haimg's user avatar
  • 1,193
6 votes
Accepted

What is this box on wall in my kitchen?

That is the old type of phone jack. Can probably add the new type of plug, or remove if you do not need it. Was used with rotary phones.
crip659's user avatar
  • 24.5k
6 votes

Phone/cat3 equivalent of network switch

A DuckDuckGo search for "phone line splitter" (or "duplex phone jack", for a more "correct" term) comes up with a multitude of responses. They all look like this little ...
FreeMan's user avatar
  • 47.3k
5 votes

Installed Electric Tankless Water Heater - Internet loss when active

Long shot...if I'm wrong I'll delete. 112 Amps is a HUGE draw. As you probably know, many houses have a total 100 Amp (sometimes less) service. If your service drop isn't significantly larger, or ...
manassehkatz-Moving 2 Codidact's user avatar
5 votes

What is this four connector-post, square electrical device mounted to my interior wall?

Other answers provide great info, just adding a picture for reference. At first glance I thought it was an RJ45 block, but this has less screws. Image from https://www.commgear.com/allen-tel-4-cond-...
Jeff Neet's user avatar
  • 151
5 votes

What is this four connector-post, square electrical device mounted to my interior wall?

It's a four-wire junction box (missing plastic cover) for connecting a phone or other customer premises equipment to one or more central office lines. It predates the use of phone jacks.
Phil Freedenberg's user avatar
5 votes
Accepted

Installed Electric Tankless Water Heater - Internet loss when active

Something you might want to consider here is that your phone line inside the house is probably something crappy and unshielded. Cat3, for instance, offers virtually no shielding at all. What I would ...
Machavity's user avatar
  • 24.8k
5 votes
Accepted

Why do phone and cables companies leave their cables behind, and what to do about it?

They do it because they can. It costs money to remove cables. If the municipality doesn't require them to do so, why would they? Most people don't notice or complain, and there's the off chance they'...
isherwood's user avatar
  • 138k
5 votes

Testing phone installation without phone service

There are devices called phone line simulators which you can hook up standard handsets or modems and it will simulate connections. It can simulate calling and ringing as well. Here is a popular vendor:...
DaveM's user avatar
  • 2,715
5 votes

Phone/cat3 equivalent of network switch

'POTS' doesn't use switching at all, unlike Ethernet. Ethernet is point to point, every cable must be terminated at a 'host'. POTS can be split, joined, starred, anything. So long as all the wires ...
Tetsujin's user avatar
  • 11.5k

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