Repurpose telephone wiring for Ethernet

[LeifB]

I'm sorry if this has been explained elsewhere, but I haven't had luck finding an answer.

 

I recently purchased a home (late 1980's construction) and have RJ11 (telephone) jacks in most of the rooms connected with traditional 2-pair wiring (NOT Cat5/6). With the move, we disconnected our landline and now have no use for the telephone jacks, but they are conveniently located where I would like to have network connections. I understand that traditional telephone wiring was 2 pair instead of the 4 twisted pairs in Cat5/6. Since LAN connections only use 2 pairs anyway (as was kinda referenced in the "There's no way this works - Debunking bogus Network Splitters" video a few months back), would it be possible (if the lines are all dedicated runs and not loop connections), to convert the runs to ethernet by matching the pin connections on either end of the runs with their respective male/female RJ45 connectors or faceplates? I've seen some articles saying that it isn't worth it because you can only get 10 Mb/s over telephone, but they use the same conductors in both cables (just more twists). Has anyone had any luck with this?

 

 

[Dutch_Master]

Over time you'll be ripping out the old phone wiring anyway (resell value increase!), so you may as well pull new Cat6A cable (at minimum) or fibre (best solution) though the phone conduits right away.

[Zando_]

21 minutes ago, Dutch_Master said:

Over time you'll be ripping out the old phone wiring anyway (resell value increase!), so you may as well pull new Cat6A cable

 ^^^ Use the phone lines as handy cable pullers to pull new Cat6A.

24 minutes ago, Dutch_Master said:

or fibre (best solution) though the phone conduits right away.

Is there an actual purpose for a fiber home LAN?

[LeifB]

Just now, Zando_ said:

 ^^^ Use the phone lines as handy cable pullers to pull new Cat6A.

Is there an actual purpose for a fiber home LAN?

When the cables were installed originally, they did it properly and tacked the cables to the floor joists and wall studs. Pulling new would require cutting holes and using the old as wire pulls won't work because of the supports. Found this out trying to run a new cable for the furnace.

 

As for fiber at home, that's an investment I have no interest in getting into at this time. Maybe someday, but today is not that day.

[LeifB]

30 minutes ago, Dutch_Master said:

Over time you'll be ripping out the old phone wiring anyway (resell value increase!), so you may as well pull new Cat6A cable (at minimum) or fibre (best solution) though the phone conduits right away.

With all the stuff we had in the last move, I'm planning on being in this one until I need to be moved into a nursing home. As for pulling new cables, the basement is finished with drywall on the ceiling. I really have no interest at this time with cutting that many holes in the ceiling when my Wifi6 router seems to be handling things for the moment. The cables are there and I'm just trying to figure out if this is something worth pursuing. 

 

As for the fiber option, that one is going on the back burner until I win the lottery and pull the same setup that Linus is doing at his place with a central server room with all the computers there.

[GOTSpectrum]

It depends... 

 

If the phone cables are high-quality and twisted, you may get 100Mbit over it. But it would make more sense to just run new cables. I understand you can't pull new cables but I'm sure you got a drill right? Run them externally 

[LeifB]

3 hours ago, GOTSpectrum said:

It depends... 

 

If the phone cables are high-quality and twisted, you may get 100Mbit over it. But it would make more sense to just run new cables. I understand you can't pull new cables but I'm sure you got a drill right? Run them externally 

While I'm not against cutting holes in the walls and ceiling to run new cables, I'm not ready to repaint the entire basement right now. A construction project I'm overseeing had a lot of discussions about network cabling (Cat5/6) vs communications wire (thermostat, 3-pair telephone) and how Cat5/6 could be used for all. I wasn't sure if picking the pairs for the 3-pair could work in reverse.

 

Looking at the wires more (I wasn't home when I initially posted), the 3-pair telephone cable is not twisted which would make it very susceptible to electromagnetic interference. Without the twisted pairs, it looks like my question would be better phrased as "This SHOULD work, but is it going to be something usable?"

 

Eventually (when I get permission from the Boss/wife) I will be looking to run Cat6 cables throughout the house, but I was thinking that this may be a functional intermediate step while I wait for permission.

[Falcon1986]

7 hours ago, LeifB said:

Eventually (when I get permission from the Boss/wife) I will be looking to run Cat6 cables throughout the house, but I was thinking that this may be a functional intermediate step while I wait for permission.

Wait to run ethernet. You'll have less headaches regarding your network in the future.

 

BTW, do you have coax runs?

 

5 hours ago, Jack Harryy said:

phone links and connectors are worked off of for the most part a similar stuff, I'd envision. Ethernet RJ45/8P8C was worked off of a similar spec.

What?

[LeifB]

2 hours ago, Falcon1986 said:

Wait to run ethernet. You'll have less headaches regarding your network in the future.

 

BTW, do you have coax runs?

 

What?

I have both coax runs and 3P6C telephone. I just don't feel like buying converters if I could just swap the ends of the telephone (if it would work). Smaller investment for an experiment. especially if I'm just going to run new Cat6 cables down the road since wifi is currently handling everything I'm throwing at it.

 

I think I know where Jack was going about the specs. The requirements for the wires specifically are very similar between the 3P6C telephone and 4P8C Cat5/6 cables. Where they differ is with the assembly and twisting of the wires but the physical wires that are used are the same. I think that was where Jack was going.

[LAwLz]

16 hours ago, LeifB said:

I understand that traditional telephone wiring was 2 pair instead of the 4 twisted pairs in Cat5/6. Since LAN connections only use 2 pairs anyway (as was kinda referenced in the "There's no way this works - Debunking bogus Network Splitters" video a few months back), would it be possible (if the lines are all dedicated runs and not loop connections), to convert the runs to ethernet by matching the pin connections on either end of the runs with their respective male/female RJ45 connectors or faceplates?

I haven't seen the video you are referring to so I don't know what impression you got from it, but yes it is true that you can do RJ45 ethernet over just 2 pairs of wires (a total of 4 copper wires).

Some things to note however is that:

 

1) You will only be able to get a maximum of 100Mbps over those cables since the 1000Mbps standard requires all 4 pairs to be present.

 

2) Your old telephone cables might just be UTP-3 cables, and those can have pretty significant crosstalk. As a result, even if you manage to negotiate 100Mbps over them, expect to get less because of errors on the link.

 

3) Some features like PoE may not work if you only have two pairs of cables. But that depends on several other factors. Just be aware that some things assume all cable pairs exist.

 

 

Would it be difficult to rerun all the cables? I honestly don't think this sounds like a great idea. It's possible in theory, but will probably cause quite a few headaches and not work as well as expected.

[LeifB]

5 hours ago, LAwLz said:

I haven't seen the video you are referring to so I don't know what impression you got from it, but yes it is true that you can do RJ45 ethernet over just 2 pairs of wires (a total of 4 copper wires).

Some things to note however is that:

 

1) You will only be able to get a maximum of 100Mbps over those cables since the 1000Mbps standard requires all 4 pairs to be present.

 

2) Your old telephone cables might just be UTP-3 cables, and those can have pretty significant crosstalk. As a result, even if you manage to negotiate 100Mbps over them, expect to get less because of errors on the link.

 

3) Some features like PoE may not work if you only have two pairs of cables. But that depends on several other factors. Just be aware that some things assume all cable pairs exist.

 

 

Would it be difficult to rerun all the cables? I honestly don't think this sounds like a great idea. It's possible in theory, but will probably cause quite a few headaches and not work as well as expected.

This is kinda what I figured, especially after confirming that the telephone cables were not twisted. I wasn't expecting to get max bandwidth, but the cross talk causing communications errors might tank it more than I was expecting.

 

I don't have any POE devices so that wasn't going to be a concern (at least not yet). As for running new cables, the boss (and me to be fair) aren't enthusiastic about cutting a bunch of holes in the walls and ceiling of the basement to try and run them right now. I'm going to want flexibility in locating devices in the future (wife likes moving furniture around) so permanent cables are going to need a lot of planning.

 

Thanks!