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I want to split the incoming phone wire across 5 rooms. For ethernet, I use a simple Netgear switch fed from my cable modem and then 5 ethernet connections going out of the utility room to each room of the house. But when I searched "phone switch" on both Google and Amazon, I was getting Netgear ethernet switches in results and nothing for phone/cat3.

What is the phone/cat3 equivalent of an ethernet switch? I want it to have female cat3 jacks just like the Netgear has femalele cat5 jacks. I want it to be exactly the same as Netgear except phone/cat3.

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  • 3
    A single phone line can be tied together, but it is not switched in the way that TCP/IP is. All lines use the same data (think broadcast traffic), so anyone picking up any phone would hear anyone else on any of the five phones. Why do this at all? Much telephony is not power outage resistant now and wireless phone bases eliminated the need to wire every room 25 years ago. Mar 31, 2023 at 15:47
  • 2
    Phone and Cat3 are not the same thing. Phone wires use RJ11 plugs and sockets connected by any wire at all, not Cat (Category) anything with connections that can be anything at all, even twisting and taping wires together. Ethernet uses RJ45 plugs and sockets and the wires, connectors, and connection methods all have to be to certain specifications. Cat3 is one of those specifications, highly outdated that serves no purpose any longer. So: what are you actually trying to do?
    – jay613
    Mar 31, 2023 at 16:24
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    One point I haven't seen others address: With old-style phones at least, you had to give the phone company the "ringer equivalence numbers" if you were going much beyond three instruments, so they could be sure the line could supply enough current to ring all those mechanical bells. Electronic phones and modems and other modern phone equipment generally has RENs down around 0.1 so this isn't generally an issue now -- but if you want to use Grandpa's old rotary dial phone, or something even older, you may need to talk to the phone company about this parameter.
    – keshlam
    Apr 1, 2023 at 1:42
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    I hadn't even considered REN these days, forgotten all about it - this links to a British Telecom document explaining how the standard maximum REN is 4, but you can juggle that all the way up to 11 using hardware 'extension booster' boxes. shop.bt.com/content/uni2/documentation/4kqv/bt-ren-booster.pdf
    – Tetsujin
    Apr 1, 2023 at 15:02
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    Most modern telephone services will take pulse dialing, but your phone has to be well adjusted, as the tolerances on the pulses are much tighter now that they are digitally analyzing them rather than using them mechanically. The trickier part is their mechanical bells. They tend to work on services provided by actual traditional telephone companies designed for whole houses (like FiOS), but cable and VoIP only companies tend to use systems that truncate the sine wave and/or don't provide the full voltage necessary to drive the bell striker, even with enough REN support.
    – jgd
    Apr 2, 2023 at 11:25

6 Answers 6

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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. POTS wiring has been doing it this way for decades.

OK, that said: If you want to do any "future proofing" you should consider running cat-5 or cat-6 with each jack going to a central point (star config) where the POTS service comes in. Then simply connect all the POTS lines in parallel. If you wanted to get a bit more fancy, get a low voltage cabinet and a punch down block to make the connections. So if you eventually give up on POTS service, which many of us have, you'll have the wiring in place to upgrade to LAN/ethernet/internet.

Again, if you want to keep it super simple, just run the cable from one POTS (RJ11) jack to the next. It won't be future proof though.

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    Yeah, using actual CAT3 wire (if you can even find it these days) is a bit nuts. Heck, the last two jobs I worked even the 25-pair phone cable was Cat5e. That'll run 6 gigabit ethernet connections and still have the slate-violet pair available to run POTs on.
    – Ecnerwal
    Mar 31, 2023 at 16:26
  • The oldest cables in my building look like they were installed by Alexander Bell himself, sticky fabric-wrapped monstrosities. Newer ones are just bell wire (no relation;) Even the newer ones are decades old. I've never replaced one & I've been here 30 years; reconfigured twice as the house layout was changed, but never went to the trouble of replacing one. All still works, one odd occasion we have need to use the landline. [For the past 20 years it's been unplugged unless we want to dial out. It gets used for 'hanging on the phone'-type consumer services free calls only.]
    – Tetsujin
    Apr 2, 2023 at 14:36
9

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 case 4 or 6 wirenuts will do the job.

Or you could get a 6-port surface mount box with 6 jacks and hide the pair of wirenuts inside it. That would "look like" (vaguely) an ethernet switch.

Leviton 6-port surface mount picture from GordonElectricsupply.com no endorsement implied

Connect wires to the green/red or white-with-blue/blue connection points on your jacks, and connect all the blue or red and all the green or white-with-blue wires. Or spend ~12 or more times the price on a manufactured item you can plug in to. I don't recommend that, as it's an extreme waste of money, but PT Barnum is widely alleged to have known why they make it.

Leviton 476TL-T12 picture from GordonElectricsupply.com no endorsement implied

If you're not dead set on having jacks (which it seems you might be) you can simply use a junction box to run all 6 cables into, and hide the wirenuts joining the appropriate wires.

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  • this is exactly what I want. what is it called?
    – amphibient
    Mar 31, 2023 at 16:15
  • A 6-port surface mount box. With or without additional descriptors like "keystone jack" that are not usually required to find them. They tend to come as 1, 2, 4, 6, 8, or 12 ports, typically, though other numbers are not impossible, just not the usual.
    – Ecnerwal
    Mar 31, 2023 at 16:16
8

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 chain manner with the incoming cable run to the first location, then on to the next, until all the locations are served. It sounds like you've run the incoming cable to a central location, and then run individual cables to each service point. To connect them together you can use a phone block such as [this] which you can order online 1.

If you haven't run the wiring yet, you might want to use Cat 5 or Cat 6 wiring and terminations. This will allow it to be used for either telephone or ethernet in the future, including VOIP.

6

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 beauty:

enter image description here enter image description here
images courtesy of homedepot.com. No endorsement intended or implied. Click all images to embiggen.

The HD also sells triplex versions for one in, three out. I'm sure that, at some point in time, one could purchase 4- or 5-output versions of them, too, but fewer people need that many land-line jacks anymore, so they're becoming a bit of a dinosaur.

Internally, these are nothing more than incoming lines to a punchdown block that the outgoing lines are connected to. There are absolutely no smarts inside this thing at all. That's what allows you to pick up two handsets and have a "conference" call at your end.

The good news is that the duplex one (currently) lists for less than $3, so you don't have to pay expensive network switch prices.

If you need more lines, you simply daisy chain more devices.

The other option is to install a puchdown block like this one:

enter image description here
image courtesy of amazon.com. No endorsement intended or implied

You put your incoming line into the blocks on the left (using a punch down tool), then run one line from each of the blocks on the right to wherever you need them. This, plus the tool, are considerably more expensive than the little outlet duplexer above, but are probably more reliable.

For a dirt cheap, DIY solution:

  1. Drill 4 holes into a piece of wood.
  2. Epoxy a nut over each hole.
  3. Run a bolt and two flat washers through each nut.
  4. Strip your phone wires
    1. Clamp all the red wires between one pair of washers
    2. Repeat for the blue, yellow & green wires, each on their own nut/washer/bolt set

You've made your own "punchdown" block. This is, literally, all there is to it.

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  • I need a box that will encapsulate all this
    – amphibient
    Mar 31, 2023 at 15:48
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    So make/buy/customize a box. There's nothing about splitting POTS that's rocket science.
    – FreeMan
    Mar 31, 2023 at 16:27
  • In the US for "actual phone two-pair" it's green/red and black/yellow and for a one-line system it's only green/red (or white-with-blue, blue on network wiring)
    – Ecnerwal
    Mar 31, 2023 at 16:31
  • For years, @amphibient, I had a screw down block (equivalent to a punchdown block, but with, you guessed it, screws) in my basement splitting my incoming line into 3 or 4 outgoing connections so I could feed jacks throughout the house. I never had a cover over it, and finally removed it a couple of years ago (despite having given up on a land line nearly a decade ago). A box/cover is purely decorative and only necessary for WAF.
    – FreeMan
    Mar 31, 2023 at 16:35
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    @Criggie i want the flexibility
    – amphibient
    Apr 1, 2023 at 13:47
5

'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 connect eventually to all the end points, it works.

All of these will work…

enter image description here

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  • how do I split one incoming line into 5 cables going out ?
    – amphibient
    Mar 31, 2023 at 15:48
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    You just run them all into a bit of junction strip/box. POTS is really not fussy at all. At a push you could just twist them all together & wrap some tape round it [I wouldn't, but you could].
    – Tetsujin
    Mar 31, 2023 at 15:50
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    Don't compare POTS to ethernet. They are 100 years apart in technology. It doesn't need to be modular, it doesn't need jacks & sockets [other than where it comes out of the wall to the actual phone.] It doesn't need nice punch-down connectors. It's Victorian. All it needs is continuity on two wires.
    – Tetsujin
    Mar 31, 2023 at 15:54
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    What's wrong with a bit of connector strip? Stick half the wires in one side, half in the other. Done. You're not going to be putting this on the mantlepiece for all to admire.
    – Tetsujin
    Mar 31, 2023 at 15:56
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    You're seriously over-thinking this. All you need is continuity on two wires to all end-points. Anything more is just decoration, fluff, frippery. It's not like you're going to be reconfiguring it every other weekend. Also bear in mind it's harder to re-use punchdown connectors $2 each [+$25 for the tool] than terminal block $0.20 for a dozen. It's also considerably tougher to get more than one wire in any punchdown.
    – Tetsujin
    Mar 31, 2023 at 16:01
1

I concur with everyone saying it's a waste of money, but a Google search for "telephone distribution tap" produced a bunch of options, like:

  • This Leviton block, which lets you punch down a single incoming line into a 110 block and turn it into 7 RJ11 jacks:

  • This slightly cheaper block that does away with the RJ11 jacks and lets you punch down up to ten cables onto interconnected 110 blocks:

  • And the same box Ecnerwal posted.

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