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NBN With Multiple Phone Outlets

Australia's NBN, how it will affect your existing landline phones when you are migrated depends on how your home is currently wired and how many phones you have.

There's been a bit of rubbish being spread by RSP (Retail Service Provider - AKA: ISP) sales type people telling you your existing phones wont work when you're moved to the NBN. There is some truth to this, but no you likely do not need to re-wire your entire house or some such rot, or buy dect phones as only means of more phones, as many are being told, and despite other rhetoric from these sales geniuses, you can have more than one fix wired phone.

There are issues with leaving multiple active outlets in place on your original phone line when NBN connects your new service with their VDSL modem that's for certain, they can and do create issues that result in poor performance with your service, that's one of the few things NBN chief Bill Morrow and I actually agree on ;-)

There are typically two wiring layouts of a home with multiple outlets and ADSL, the first and most common is daisy chained, that sort of looks like this

(if any diagrams look incomplete, click on them for full size)

If you have such a setup, NBN may or may not (but should) disconnect the rest of the sockets from that first socket, also known as NBP (Network Boundary Point) in the chain, if they don't, you'll need to have a Registered Cabler do it for you (I heard recently that to stop many trivial NBN connection and speed complaints, that NBN techs are now doing this), and, if you want your other phone points to work again, you will need a Registered Cabler to come and make those changes anyway, in most cases, it's a matter of doing a little bit of wiring work at the first outlet, changing over the face plate and popping a couple more sockets in, much like figure 2 below

We see with the single gang outlet the first socket is the active NBN line and connects to your VDSL modem, the second and third sockets are linked together on a separate two gang plate adjacent to the single, you take your voice out from the VDSL modem and plug it in to a socket on the second plate to distribute your voice service through to all other analog phones, and you can plug in an analog phone into the third socket, so you have a phone right there with your modem.

We can not use a three gang outlet to keep things clean and visually appealing, sure it would look better, less holes in your wall and so on, but this is another one of the stupid NBN regulations, they cant just claim the socket, they want the whole damn plate, hole and all.

Another, less common wiring setup would be what's known as star wiring, this is where multiple cables are run from a central point, usually the Telstra (or now NBN) NTD (Network Termination Device), a big brownish looking box on side of your house next to your power box, as shown below

In this case, your costs will be a bit more because a Registered Cabling Provider will need to do a lot more work, like disconnecting all but the modem line, and altering your cabling similar to the previous example, or re-star wire your other sockets from a new central point close by your modems socket, there are various ways this can be done, in most cases they can still re-use some (if not all) of your existing phone cabling.

It's important to note that just because you have the big NTD box on your wall outside, doesn't mean you have star wiring, you may still have a daisy chained system.

Since early 2017 Telstra, and now NBN, will only install and cable your lead-in up to an NTD, rather than a wall box and first outlet, on all new installations. This means the builder, or home owner, will need a Registered Cabler to do the actual wiring of the home and connect that to the NTD.

These are not all the wiring configuration possibilities, but they are the most common, so obviously existing daisy chain setups are the quickest and cheapest to convert, star wiring, the longest and more expensive.

The above is pretty much also applicable if you want to use an independent VoIP provider, rather than the VDSL modems voice port - which is just an ATA (Analog Telephone Adapter) inbuilt to the modem, just like many ADSL modems with VoIP ports, that's all it is, nothing special.

To use a private VoIP service, such as MyNetfone for example, using your own ATA you'll be running its phone-out (FXS) port into that new second socket at the first 3 gang outlet, rather than the voice port of the NBN modem.

Most RSP's are not divulging the SIP logins they provide on those voice ports, they seem to think it's like some state secret. Now... I don't condone it, and I wont tell you how, but there are ways around it - Google or Bing are your friends ;-)

But personally, I'd be using a private VoIP service and not an RSPs over priced voice offering anyway, because, well, it's hard for them to let go of their 90's era business models, however you can take advantage of some, like AussieBroadband, who have a bundled NBN plan that includes a casual phone plan that costs nothing for DID and inbound calls if transferring your existing number over, you can read more about ABB/Aussie in our TPG to ABB article.

Trying to use your own VoIP account on their modems likely wont work either, because they control that part, with you unable to even access that section of some providers modems.

Whether using an over priced voice inclusive plan an RSP offers, or using your own private VoIP service, I hope you're now more informed on what happens to your house wiring, and what changes you might have to have made.

Recommended: our Telco and Data - Electrician or Registered Cabler? article.

WARNING: It is a criminal offence in Australia to tamper with, alter, or perform any phone or data work if it is, or even if it can be, used on or over a telecommunications or data network, rightly or wrongly this also includes cabling behind air-gaped WiFi devices - unless you are an ACMA accredited Registered Cabling Provider with appropriate endorsements.

Penalties such as on-the-spot fines of $2040 plus for minor breaches, or in more serious cases, court imposed fines exceeding $90,000 and a criminal conviction recorded is a real probability, as well as the likelihood of the removal of all illegal cabling, also at your cost.

Phone and Data Cabling can only be done by a Registered Cabler, not even an Electrician unless they also have a current Open Cablers Registration and applicable endorsements ("S" as a minimum), so if you use an Electrician, just like any person claiming to be authorised to conduct such work, you should ask to see their Cablers Registration Card, if they can not produce it for ANY reason, they must not be allowed to perform such work, an Electrician licence is not sufficient and does not authorise phone or data work.

If you're not yet on the NBN with Aussie Broadband but want to join, they run a referral system where you get 50 dollars off your first bill, if you're ready to jump on board, you can use our referrer code: 4451415 disclaimer: using this code saves you 50 bucks, but also sends some credit our way too, which will help us out greatly.


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Seamus on :

Great post, makes it rather clear on what happens, but what happens in a small business? I guess if we have a normal home style arrangement like you have shown the above applies? but what if we have multiple lines and NBN seller is telling us we need to replace our existing PABX and phones, of course they want to sell us a system costing many thousands lol

NoelB on :

Hi Seamus,

Firstly, yes you assume right, secondly, I've heard that horror story a few times too, it really depends on how many lines you have, but most pabx's have a sip module installed or as an available option, if its an old pabx, maybe not so, however, all is not lost, you can buy multi port ATA's, I might do another post on the subject of pabx's in the future as you bring up a valid question and i'm afraid so many will just fall for it and throw out perfectly good working equipment when they dont need to, in meantime when they try sell you a multi thousand dollar new system, as Dad in the Castle says "Tell em their dreamin" :-)

Seamus on :

Kewl, our office is a seven extension Panasonic PABX with four analogue Telstra lines,it's Telstra trying to up sell us into something costing five grand

NoelB on :

Ahhh yeah, I'm not surprised, telstra will never change, all they see is $$$$$ opportunity.

For four lines you have choice of ATA's, most people are recommending a couple of cisco spa112's, at around 80 dollars each probably not bad, to do it all in one unit, with cisco - forget it, the spa8000 stuff will be way too pricey, I think closer to $400.

Grandstream are well known for reliable VoIP equipment, their ATA's, which also include a router which you wont likely need (nor have to use), so configuring it if you're doing it yourself can be a bit daunting if not familiar as there's a myriad of options, most of which you just ignore anyway, totally opposite to the spa112's that are fairly easy to configure but limited to only two ports per device.

The Grandstream four FXS port unit, the HT814, supports 2 sip profiles (servers), but you can use one profile for the four sip accounts, this should suite your office needs nicely, rather than two spa112's, saving bit more money, see page 26 of

Now maths was never my strong point, but even I know that 200 is way better than 5000+ especially for small businesses.

Mr Telco on :

20 years ago when Foxtel was rolling out, they had alot of Foxtel cowboy installers who were cutting into the lead in cable to install phone lines behind the TV for Foxtel Digitals return path. At one stage Foxtel advised that was ok practice then recinded to say telecommunication contractors had to run the return path phone line from the first socket. Currently, alot of customers are having with bridge taps being identified on NBN connections that use the telephone line. The customers ISP are advising customers to engage a private technician to remove the bridge taps.

NoelB on :

Hey Mr Telco,
You're spot on, and it's not just cable TV guys. some other situations I've seen are alarm installers in the past have also chopped into the middle of LIC to hook into - like WTF.

Also plenty of in-the-middle cuts for other outlets around the place, (found that one in my own house and scary thing is who ever did it went to dick smiths or some place and bought, cut off ends and used a bloody extension lead - how many times do we see that )

And for those readers wondering what "bridge taps" are, they are what they sound like, tapping off your leadin cable to run another outlet, in years gone by, they were not overly a problem, even with ADSL, but with higher frequencies of VDSL they are a serious problem that results in poor speeds and dropouts, the above scenarios I gave in the post, (daisy chains and star wired outlets) are essentially bridge taps, workable on POTS and ADSL, but not VDSL

Don Joe on :

Interesting read, thanks for the nfo.

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