Can old phone be adapted to NBN?

[Greorge]

I tried to search for this information, but don't get any results.

Way I look at the problem is that the same plug is used and old type phone would work if it was somehow powered up.
Old phone wires carried power and signal.

My questions are:
Did anybody try this already?  - would love to get link
If not, can it be done?

My gut feeling is that I can use standard power adaptor (one of few I have collected) from 240V to 12V and then with boost device get it up to voltage that phone would operate and then find place to connect and it should work.
Not sure what voltage is, but I think it is somewhere between 20V and 30V

Possibly would have to prevent power going back to NBN modem.

[Greorge]

Surprised that nobody tried to have a look if it is possible.

Does it mean that it is impossible?

Or we are such a throw away community, that it is not an option.

[Brumby]

FYI the voltages around the old style phone operation are DC 50V (or so) when the phone is "on-hook" - where the phone is effectively open circuit to the line.  When you lift the handpiece, the phone is off-hook and the line gets loaded, bringing the voltage down to DC 20V or less.  Tone dialling occurs with the tones superimposed on the DC and pulse dialling occurs through a series of 20V-50V-20V pulses (created by alternatively loading and unloading the line) with a pause between digits.

However, connecting to the NBN, you needn't trouble yourself with all that, because there are readymade boxes that you can get - if your modem doesn't already have an RJ11 socket ready and waiting.  It will have all the voltages and signalling sorted out.

Remember, old phones are analogue and any internet based link is going to be digital.  Even then, there are choices on the digital path to take for this.  Do you want to utilise the ISPs own telephone service or your own VoIP solution?

From your question, I do not expect you have anywhere near the knowledge necessary to build your own solution.  I recommend that you do some homework and get the box to do the job.

[stj]

i'm pretty sure it's AC or it wouldnt go through the isolation transformers!

[Brumby]

i'm pretty sure it's AC or it wouldnt go through the isolation transformers!

You need to do some homework on how the old PSTN works.  Your comment is only appropriate for independently powered devices that attach to it - such as a fax machine or an old-fashioned modem.

[Nusa]

Aside from the answers probably being regional, one must define "old".

[Monkeh]

I tried to search for this information, but don't get any results.

Way I look at the problem is that the same plug is used and old type phone would work if it was somehow powered up.
Old phone wires carried power and signal.

My questions are:
Did anybody try this already?  - would love to get link
If not, can it be done?

My gut feeling is that I can use standard power adaptor (one of few I have collected) from 240V to 12V and then with boost device get it up to voltage that phone would operate and then find place to connect and it should work.
Not sure what voltage is, but I think it is somewhere between 20V and 30V

Possibly would have to prevent power going back to NBN modem.

If they don't supply the power to run a phone, why do you think they have anything listening on the other end?

It's either a phone line or it isn't - if there's no DC bias, it's not a phone line.

[johnh]

Short Answer No

Long Answer: 

You will need Voip POTS to VoIP gateway and sign up with Voip provider.  Most of the retail provider have a Voice offering were you plug your phone into the router they supply.

NBN used to provide a voice only solution over the FTTP ( No data )  You plugged your old POTS phone into the modem and it went VoIP to what ever provider you  signed up with

[Greorge]

Thank you very much for replies.

I just thought that if old type cordless phone is OK for fibre NBN connection, so with some modifications older style corded phone could be kept alive with new technology too.
Looks to be wrong here.

Will have a look inside and try to salvage something for future projects.

[IanMacdonald]

All analog phones are basically similar, although the old ones use pulse dialling rather than tone dialling. Some modern systems may not recognise pulse dialling. 

Basically the supply is about 30-50v but with a high series resistance.  When the phone goes off-hook the line voltage drops to somewhere between 8v and 12v. Ringing is accomplished by applying low frequency AC to the line.

If you don't need to phone to ring, it will typically work OK from 12v supply with a series resistor of a few hundred ohms.

It's all very imprecise. Designed that way to be tolerant of long lines with lots of volts drop. 

[Greorge]

It sounds great to me.

I have 3 other phones (cordless) making ringing, can hear them even outside the house.

Have a number of power supplies from 3V to twenty something.
Have about hundred of different value resistors, all 0.5W, so surely something will come close enough.

This would save me looking for 4 phones set to match pre NBN phones distribution in my house.

Only problem is I cannot design solution myself, so would really appreciate some help.

[stj]

i remember seeing a project for a home "exchange" that generated background current and ringing signal etc.
it may have been in "Elektor" magazine.

[bw2341]

I'm not sure if this is an electronics question at all.

I took a look at the NBN service plans for a few Australian ISPs. They mention home phone service as an available feature.

If your NBN service plan includes home phone service, the installer should have connected the home's phone wiring to to the NBN gateway. Regular phones should work without any changes.

If your NBN service plan does not include home phone service, how do you expect it to work? There is nothing to connect to. You're on your own for phone service.

As an alternative, you can subscribe to an over-the-top VoIP service. OTT VoIP providers connect over the regular Internet data connection. They use an ATA (analog telephone adapter) which has a regular phone connection and an Ethernet connection. You are responsible for connecting your phones to the ATA and the ATA's Ethernet to your router.

[SL4P]

OP, go search for VoIP ATA (Analog Telephone Adapter)...

Many new internet ‘gateways’ have one or two built in, or you can buy 3rd party boxes like the old SPA-3102 etc.
These have a VoIP digital IP) service on one side of the box, and an almost standard POTS handset interface on the other side.

With configuration through a web interface (or provisioning), this can support incoming and outgoing calls on most analog handsets.  Support for pulse dialling needs to be checked on a case-by-case basis.

[Greorge]

Might have a look at second phone outlet on NBN modem.

Installing fellow said that one of them will have phone and the second one will be dead.
I will check if by any chance both outlets have the same phone line connected to it.

Second option will be splitter on working phone outlet on NBN modem and have second cordless phone connected to second outlet on splitter.
Not sure if modem is strong enough to send signal to both cordless phone bases.

Would not like to kill NBN modem making tests.
Does anybody know if it is not going to mess up the NBN modem?

[SL4P]

Usually if your gateway/router has RJ12 jacks for phone - it will also have two LED indicators in n the front - to indicate which of either or both are active.
You can actually request two different numbers on the two jacks.

[Brumby]

Would not like to kill NBN modem making tests.
Does anybody know if it is not going to mess up the NBN modem?

Look for a R.E.N. value on the modem.  It is a measure of the load it can support.

Then look at the R.E.N. for each phone that will be connected to the line at the same time - and add these up.  This represents the load presented by the phones.  As long as the total R.E.N. of the phones is not greater than the R.E.N. of the modem, you should be fine.

If you have a really old phone with pulse dialling, then there may be some other things to address - but one thing at a time.

[bw2341]

The second phone jack would be for customers who’ve ordered a second phone line. If the technician says that it’s dead, that means that you aren’t paying for a second line.

Modern cordless phone systems draw very little power from the phone line since they have their own power adapters. I usually see REN ratings of 0.1 which would allow a REN 3.0 gateway to support thirty cordless base stations. REN 1.0 represents the load of an old-fashioned corded phone with a mechanical ringer.

If too many phones are attached, some or all of them may fail to ring. You should still be able to make an outgoing call. The phone port should be able to detect serious wiring faults and shut itself down to prevent damage. That will interrupt the phone service.

[Greorge]

The second phone jack would be for customers who’ve ordered a second phone line. If the technician says that it’s dead, that means that you aren’t paying for a second line.

I plugged my cordless phone to second outlet on the NBN modem, dialled my mobile and mobile phone rang.
I called my home number and it gave busy tone.

Looks that home phone is available on either outlet, strange as fellow said that if one outlet doesn't work simply plug into other one and should be fine.
Since I tried while he was still here and the first outlet worked I didn't try the other one as it was supposed to be dead.

One possibility is that only one outlet works, which I can only find out by connecting second phone to other outlet.

Well, have to charge my other cordless phone as it wasn't used 15 years or more, might even have to get new battery for it.
Maybe the old one will hold enough charge to do some tests with it.
(Crap if I know where I put the charger for it)

[Greorge]

After so many years, 3.6V rechargeable went down to 1.6V with 5W 10 ohm resistor across terminals.
I charged it with three rechargeable batteries first, for an hour or so, until I found correct supply transformer.
By that time voltage went up to 3V.
(Old phone battery is made off 3 half size AA rechargeable batteries)

Then I charged it for several hours on a phone base.

I didn't leave it on the base overnight, as would not like any surprises like magic smoke or worse.

Battery kept charge overnight and I even made 20 minutes call, so battery isn't quite dead yet.

When I got outside call and answered using old phone, for some reason answering machine on the one with 3 handsets started to record the call on answering machine even if it didn't ring 6 times to activate answering machine.

When I find splitter, will try to use one outlet on NBN modem to see if answering machine on main phone behaves  any different.

If not, I still have 4 handsets 

[Brumby]

A splitter is easy enough - just parallel as many connections as you need (within REN limits).

So long as you don't use any pulse dialling handset to dial a number, it will work fine.

[Greorge]

Used splitter to put both cordless phones on one outlet on modem, but the same happens.
When old cordless is answered, answering machine on new cordless starts announcement.

Old one has REN 0.3 with one handset and new one with 3 handsets has REN 0.1
So all well under upper limit of 3

I have to turn off answering machine and see if incoming call answered with old cordless will activate answering machine or not.

After 6 rings or so, answering machine is turned on by the base anyway, so if this trick works I'll be happy.

If not, I will be still happy that I have 4 handset to answer the call   

[Brumby]

Used splitter to put both cordless phones on one outlet on modem, but the same happens.
When old cordless is answered, answering machine on new cordless starts announcement.

That's going to be an issue with the new cordless.  I can't see it being anything else.

[Greorge]

After 6 rings or so, answering machine is turned on by the base anyway, so if this trick works I'll be happy.

No, base doesn't turn answering machine on after 6 rings.

No big problem, still success.