Confused about Ethernet wiring in new home

Is this part of a SOHO (small office, home office ) DIGITAL phone system? the 2 large cables (trunk lines I think is the term) are a clue it's attached to a KSU. Also, the connectors shown are typically used on phone lines. The smaller cables should have printed on them the type of cable. The blue ones look like cat 5, the grey ones look like cat 3 (not suitable for ethernet). Repurposing some of might be possible. But, and here's the big BUT if the phone lines are not all "home runs" and are daisy chained (common for POTS phone wiring), you can't re-use them. They're also probably cat-3, again, not suitable for ethernet.

All you can do is start tracing circuits. Get some testing equipment at go at it.

Read the jacket - I think I can see, but not make out, faint red printing on at least two of the gray cables in your picture. But there's no guarantee that all the gray cables are the same, if this system grew organically over time rather than having been all installed at once.

Even if it's CAT3, it will run ethernet (slowly by modern standards.) That will be fine for a printer that plugs into ethernet, and other uses that are not too demanding, but won't suit your faster goals - in which case you might examine how it's installed, and whether you can use the current cables to help you get new cables into the places you actually need faster connections.

Your best bet at this end would be to install a patch panel, rather than "plugs on cables" - plugs on fixed cables are iffy (they tend to fail,) while a patch panel is quite reliable, (and also easier to connect to) and helps to organize the mess.

You'll also need a switch, to get the signal from a cable leading to your router to all the other cables (or all the other cables you are actually using.)

Beware that as phone wiring, there's no guarantee that the wiring completely respects a "star" configuration (each cable here leads only one place) - some legs of the apparent star may be "daisy-chained" to more than one outlet, and that does not fly with Ethernet like it does with telephones.

This was clearly being used as telephone wiring. Even if some of the cables are ethernet cables they have been cut and spliced for phone use and there may be splices hidden in the walls similar to what you see here. That's ok for phones. Even if some of them "work" for ethernet they may work slowly. You will not know, you'll just blame your ISP.

My suggestion is don't use any of this for internet. Buy good Cat6 or better cables. Don't buy the cheapest ones on Amazon, but good ones with good reviews. Run cables to a few critical spots in your home from a central location. Buy and install a mesh network with wired backhaul (so the mesh nodes all use your new cables) and buy a small switch if needed to connect it all together.

All this will cost a few hundred dollars and is worth the investment in your new home.

The grey stuff is often non-twisted pair, or unshielded twisted pair. As others have said, read the label.

The blue stuff could be cat 3 or cat 5, but unless you have access to both ends, it's a crap shoot whether it has a continuous run. You may be able to figure some out by temporarily unhooking wires, and seeing where you have dial tones.

You have some decisions to make:

• Do you need wired LAN throughout your house. If you do lots of internet file sharing, or run a home server, then the answer is yes, at least between the server and your internet access device. If you stream TV at anything above default resolution you will want a wired link between the internet access point and the TV device.

• You may also want it if you have several people who want to use high bandwidth applications at the same time. SOHO operations that use cloud SaaS may need this.

• Wifi works pretty well. But the closer you are to the wifi access point, the faster it is. You may want LAN between your internet access point and your wifi units at various places in the house.

In its simplest form all your house wires come to a patch panel. There a short patch cable runs from the panel to your switch.

Wire for stuffing in walls isn't stranded. This gives it less electrical resistance, but also makes it stiffer. It has less tolerance for being bent. Patch cables are either stranded, or are made from softer copper.

The wiring workmanship shown here, no matter what the cable type is, cannot be relied on to yield satisfactory ethernet operation. The way twisted pairs are untwisted for several inches, with the individual wires crossing other wiring in an uncontrolled fashion... stubs of old parallel connections just left dangling... if it works, it is still likely to cause and/or be sensitive to RF interference. The reason the wires are twisted in a twisted pair cable is NOT mechanical and NOT a stylistic or manufacturing choice.

If the actual intent is running a DSL line to a router, it could work - unlike ethernet, DSL is DESIGNED to work around imperfectly done wiring. However, even DSL cannot always deal with a so called bridge-tap situation that might be present here (multiple lines wired as parallel circuits, even if there is nothing connected at the end of the circuit - all these communications technologies work with RF electricity; the concept that a circuit with no load connected does not matter is NOT true with RF).

Technically, yes. When my roommate and I got our first cable modem some 20 years ago, a friend of his ran Cat3 into my room (he had lots of the stuff) and wired it up and it worked well enough for the 2 years we lived there.

I say technically because he simply provided the minimum Ethernet needs. Ethernet uses only 4 wires to work on the data end, so his friend crimped RJ45 jacks on using only pins 1, 2, 3, and 6. There's two major caveats here

1. Cat3 isn't designed for shielding at all. Shielding is somewhat important to Ethernet. In my case, the wire was stuffed under the baseboard down a hallway (where there's virtually no interference). It was also a 10MB network, not the 1000MB you commonly find today.
2. You can't run any Power over Ethernet (PoE), since pins 4, 5, 7, and 8 are all missing.

So you can try and it might be passable for a home network, but it isn't the right tool for the job and it may not be forward compatible.