Worth knowing in this context:

Telephones only want a twisted pair. Ethernet, popular with businesses for decades, also wants a twisted pair. Now, that pair must meet much stricter criteria to be suitable, such as Category 5 (for 100Mbit) or Category 5e (1000Mbit ie Gigabit) - but it really is just twisted pair cable, merely a tighter specification than your phone.

Suppose you are a sparky (electrician) and you have some jobs where you are to install telephone connections, some where you put in "Ethernet" (presumably 100baseT would be fine) and some they specifically want you to wire for Gigabit.

You could go to your wholesaler and buy a reel of Cat3 phone cable, a reel of Cat5 100baseT Ethernet, and a third reel of Cat 5e Gigabit cable, and take the right one for each job. So long as you do this flawlessly you can probably save a few pounds every year by using a slightly cheaper cable for some jobs.

Or, you can buy one reel of Cat5e and use that for all these jobs and since it's the same reel you can't have the wrong one and don't need to check paperwork to know you've put the correct cable in a duct etc. Thought that was a phone line but now the client insists it's data? No problem, they're the exact same cable, just smile and agree.

When I bought the place where I live now I wanted GigE to this desk, even though the DSL comes into a different room. I didn't love the idea of cutting holes in walls but I was resigned to maybe needing that, except there's a phone extension in this room (like the author says, we do love phone extensions) and so that room the DSL comes into has a twisted pair to here. I opened up the box, and I'm like huh, that's Cat5e, and sure enough this entire building was wired with Cat5e because like I said, why not, it's basically the same cable, why carry a separate reel?

So I changed the face plates from telephone to Ethernet, and I'm done.

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ninkendo 9 hours ago | parent | next [-]

I had the same thing in the house I bought, it was a nice surprise… there were 6 different phone jacks around the house in great locations for Ethernet (WiFi access points or just for a computer), and they all led down to the furnace room where they attached to a punch-down panel (basically they were all spliced into each other.)

To my surprise they were all cat5 cables. With the house being built in 2003 this was surprisingly forward-looking.

I capped all the cables that were on the punchdown panel and put a switch in there instead, and replaced all the wall jacks with RJ45, and bam, working gigabit around the house, including PoE for my WiFi access points. Still haven’t had to punch any holes in the walls.

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jonpurdy 8 hours ago | parent | next [-]

Same; this was the nicest unexpected surprise about buying this place.

Condo built in 2006 with cat5 . Two bedrooms + living room all wired with rj11 phone jacks. Just snipped those off, wired up rj45, and attached the other ends in my utility closet to a patch panel with rj45 as well.

I don't know if it's just cat5 or 5e, but it saturates a 2.5Gbe link and in-wall cable length is about 15-25 meters.

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jorvi 8 hours ago | parent | prev | next [-]

The only problem with this is that for some god-afwful reason, anything built before the 2010s (?) placed electrical and phone sockets at hip level instead of ankle level. So you're staring at ugly sockets all day.

So sadly you still have to punch holes.

Then again, it isn't that much of a bother if all you have to do is punch a lower hole, relocate the socket and then plaster both holes up and repaint. Especially if you make it a weekend job to do the whole house at once. Or rather, the way I look at it is that it's a weekend job that will improve how the house feels for decades. Doing blind wiring (gutters) for all the ceiling lights falls in the same category.

	▲	mnurzia 7 hours ago \| parent \| next [-]
		I think electrical/phone sockets were placed at that level because many telephones were designed to hang on the wall (docking onto and covering up the faceplate) for easy access. My childhood home had one that we used this way before we got a landline.
	▲	nick49488171 4 hours ago \| parent \| prev [-]
		You can always put a blank plate over the old one and save yourself a mess of plastering.

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wffurr 8 hours ago | parent | prev | next [-]

Alas my 2009 condo conversion was wired with coax to every room instead. I've been using the coax drops to pull Ethernet cables.

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raddan 5 hours ago | parent [-]

Ahh! Don’t replace your coax with Cat5e/6! Coaxial cable has excellent noise rejection—better than Cat5e.

Instead, get a MoCA adapter like this one [1]. You can get 2.5Gbps over coax!

[1] https://a.co/d/e2FYGWj

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irl_zebra 4 hours ago | parent | next [-]

I was resigned to running cat6e up three floors because there was only coax and I needed a wifi AP up there. Came across the moca solution and it's great. I get flawless 2.5gbe from the basement switch to the third floor over coax. It's basically a little device that connects at each end of the coax and cat6 goes in and out.

Cat 6 would be better though so I could run POE from the basement switch to power the wifi AP, and instead I need to go do a much more complicated switch (cat6) -> moca adapter + power brick to power moca adapter -> coax -> moca adapter + power brick (cat6) -> POE injector (with power brick) -> wifi AP. SO I'm adding at least three power bricks to the setup, which is annoying. Otherwise it would be one cat6 drawing POE from the switch and powering the AP.

	▲	cyberax 2 hours ago \| parent [-]
		You can run power over coax! You can buy power-injecting splitters that were used to power old analog cameras. They basically just connect the cable to the 12V, sometimes directly but usually through some current-limiting safety switch. MoCA devices have a 100 Ohm internal resistor at the end to limit the cable echoes, so they are not affected by the DC on the cable.

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mrandish 2 hours ago | parent | prev [-]

+1 on MOCA 2 being excellent to solve gaps in wiring. We bought a 6000 sqft 2001 house built with in-wall RJ11, lots of coax runs and some Cat5e runs (but not enough). Due to the size the house, the electrical, HVAC and cabling is roughly divided into two halves with separate electrical panels, HVAC pads, etc.

Unfortunately, all the RJ11 and alarm wiring runs to a closet in one half while all the coax and Cat5e run to a closet in the other half - with no RJ11 endpoints near the Cat5e/Coax closet and not Cat5e/Coax endpoints near the RJ11 closet (sigh). I tried Powerline data and it only works well in adjacent rooms and not at all between the halves due to separate electrical panels. Fortunately, there were a lot of coax runs set up for two separate nets (18-inch satellite and a huge attic antenna for OTA broadcast). So, by repurposing the now-unneeded antenna coax, MOCA 2.5 gbps mostly saved the day by filling in where the Cat5e should have gone but didn't.

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jama211 4 hours ago | parent | prev | next [-]

And some cat5 cables will take gigabit speeds even though they’re not rated for it if they’re high quality enough too.

	▲	jrmg 4 hours ago \| parent \| next [-]
		Cat5 is rated for Gigabit over spans of up to 100 meters. The 1000Base-T spec predates Cat5e.
	▲	mrandish 3 hours ago \| parent \| prev [-]
		> some cat5 cables will take gigabit speeds Especially if the run is relatively short (<=100ft) and it doesn't run parallel to noisy power cables.

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j45 4 hours ago | parent | prev | next [-]

There were a lot of tech enthusiasts who put them in.

I know more than a few who did this, ethernet cable pricing had just fallen at some point to make this more accessible.

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Freedom2 5 hours ago | parent | prev [-]

My place had previous owners who had the foresight to thread the wire through PVC tube behind the wall. This means that when I wanted to add extra access points, it was easy to thread another cat5 through and pull it to where I wanted.

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throw0101a 7 hours ago | parent | prev | next [-]

> Telephones only want a twisted pair. Ethernet, popular with businesses for decades, also wants a twisted pair.

This is why there are two wiring standards, T568A and T568B, with A being compatible with multi-line telephone systems:

> The T568A scheme is based on the older USOC (Universal Service Order Code) standard, which was used for telephone wiring before the advent of high-speed data networks. The USOC standard assigned the green pair to the first line and the orange pair to the second line of a two-line phone system.

* https://www.comms-express.com/infozone/article/t568a-and-t56...

> As of 2018, ANSI/TIA still [recommended] T568A for residential installations for plug-in backward compatibility with old technology like fax machines or a plug-in base station for wireless phone handsets. If you are not using any such devices, or have no intention of plugging ancient RJ11 plugs into RJ45 wall jacks like you would a “phone jack”, then it comes back to personal preference again.

* https://www.truecable.com/blogs/cable-academy/t568a-vs-t568b

* https://www.flukenetworks.com/knowledge-base/application-or-...

As long as both ends of the cable are the same, it does not practically matter which variant is used.

* https://en.wikipedia.org/wiki/ANSI/TIA-568#Wiring

There are also A-B crossover cables (though a lot of NICs can do auto-crossover nowadays):

* https://en.wikipedia.org/wiki/Ethernet_crossover_cable

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manbart 7 hours ago | parent | prev | next [-]

Gigabit Ethernet require 4 twisted pairs i.e. 8 individual cables. 100Mb Ethernet requires 2 pairs i.e. 4 individual cables. At least in standard configuration

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stefan_ 4 hours ago | parent [-]

There is a standard for Gbit over a single pair: Single Pair Ethernet (SPE). But it's more of a rare automotive thing, so I'm also confused how the grandparent made this work.

	▲	y1n0 an hour ago \| parent [-]
		Used on rockets too. Harnessing is a major contributor to non-payload mass.

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hinkley 2 hours ago | parent | prev | next [-]

Ethernet is usually two pair, but cat5 has four. When I moved into a new apartment building I found all the phones were cat5 wiring so I was able to redo three of the outlets to do phone and an ethernet jack, then put a switch in the coat closet, which is where the wiring guys put the junction box.

I can’t recall if I put them back when I moved out. I must have, but I’ve no recollection of doing so. I think I left the junction box in the closet though.

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VLM 5 hours ago | parent | prev [-]

I pulled several thousand lines as a kid starting out in Gen-X era and you are completely correct with one scalability and labor cost issue:

Real cat5 and ethernet connectors just work and phone cable and phone plugs just work, but if you mix them you'll get all manner of expensive labor costs trying to figure out jury rigged solutions.

At one client they used two pair for business phone system, we're on a cable pulling team and one guy punches down the blue and green pairs the other side punches down blue and orange pairs (essentially a 568A vs 568B violation) and we spend SOME EXPENSIVE TIME trying to figure out why the cable toner "proves" we are on the same cable so it can't be a wiring fault.

Or the stereotype of the halfway colorblind guy at the far end working in the ceiling, on a ladder, in the dark, swaps the orange and brown pairs as happens sometimes.

Oh even funnier is there's always "that guy" who is too lazy to pull an additional cable to a new phone, so he steals some pairs from a nearby phone, somehow knocking out both phones in the process. Such a headache.

Labor for troubleshooting miswired cables/jacks is SO expensive its just cheaper at work to install phone lines using phone line parts and ethernet using ethernet parts.

The arrival of VOIP phones around Y2K, somewhat after my time, must make life so much easier. And now nobody uses wired phones everyone has a smartphone.

At home if you're doing one line and its a hobby so your time is free, then your strategy does work.