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How does a VoIP modem work?

Discussion in 'Networking, Telephony & Internet' started by Dark Heart, Sep 14, 2020.

  1. Dark Heart

    Dark Heart Member

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    I recently moved to the NBN and got given a modem/router with a phone port. The modem sits it a wardrobe hidden away.

    Does the phone need to be plugged into the modem directly? Can I instead plug the modem into the wall and use the existing phone wiring in the house?

    I was using a VoIP phone that is not "NBN supported" (at least with my ISP) .
     
    Last edited: Sep 21, 2020
  2. tuRtlez

    tuRtlez Member

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    depends on your nbn technology

    my experience with fttc

    we had a central filter installed on adsl, so what was done in this case was terminating the pair that previously went to the telephones. this will allow to use the previous internet port for the nbn modem and then use the existing phone ports in the house for the telephone. If you don’t terminate the pair at the filter for the telephone, this will cause the internet to drop every item you pick up the phone.
     
    Dark Heart likes this.
  3. caspian

    caspian Member

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    OK, for starters VoIP is not a function of a modem. the modulator/demodulator device converts an incoming data signal via some sort of carrier platform (could be voice frequency dialup or DSL over twisted pair copper, RF over coax, or GEM packetised data over fibre) into a bus you can connect your PC or router to. for consumer broadband applications, that's typically an electrical ethernet bus. so the modem is a OSI layer 1 transceiver, nothing more.

    the modem may then be stuck inside a box with a router, for consumer convenience. even if both devices are present, you may not be using both in your setup. for instance with the aforementioned FTTC connection, NBN supply a device called an NCD which is the modem. you then run an ethernet cable from the NCD to your router, into the ethernet WAN port. the modem functionality of your device, even if present, it not in use.

    if the voice service is VoIP based, then it's emulated POTS being produced by an ATA built into the router. the ATA provides POTS-like functionality like dial tone, incoming ring signal, line voltage to drive a line powered phone handset etc. the ATA then has an ethernet bus which is coupled to the router of the device internally, and it just sends its data to the router, trusting the gateway router to find a path to the SIP server out on the net somewhere.

    so yes, in that case your phone handset has to be connected to the voice phone port on the router, either directly, or by arranging the building wiring to act as an extension from the router voice port to the wall socket you want to use.
     
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  4. OP
    OP
    Dark Heart

    Dark Heart Member

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    Thanks for your responses! That clears a lot up.

    The connection that we have is HFC.

    Apologies for getting the terminology wrong.

    That's the crux of my question. Is that going to work by just plugging it into one socket in the wall or does the wiring (telephone cable) in the house need to be modified?

    Prior to moving to the NBN I was using a phone that used ethernet to connect to the VoIP service directly. The ISP has said that this is not supported (ie won't work). I don't have an older style phone to test.

    edit: actual set up:

    HFC device (supplied by NBN) -> TP-Link Archer v1600v -> Phone
     
    Last edited: Sep 15, 2020
  5. Renza

    Renza Member

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    your phone wiring needs to be isolated from the incoming cabling from the exchange before you can plug it into your modem and distribute it to the rest of your house
     
    Dark Heart likes this.
  6. evilasdeath

    evilasdeath Member

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    It will depend on the wiring of your house.

    Its definitely possible but requires the wiring to be correct.

    Given you have said you have HFC it means you will have a separate NCD and then a router likely with an inbuilt ATA.

    You need to get your street copper disconnected so your house wiring is isolated and then connect the ATA port to the wiring at some central point. Effectively the ATA becomes the head end for the ATA, just be aware that ATAs are generally not as good as the ones in exchanges, and may only power a single handset.

    Depending on your ISP and if they provide the VOIP details or lock them down into the router your choices may be limited. But if I needed to get a cabler out I would put ethernet to where you want the phone, get a separate ATA and plug the Phone into that and the ATA into the ethernet socket which goes back to your router. An ethernet socket is far more useful than a phone port.
     
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  7. MR CHILLED

    MR CHILLED D'oh!

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    This is something I need to now get "fixed". After I recently moved to NBN I now have been stuck with a phone in the study, which I don't want, but I have no socket in the study that extends to the rooms where the regular sockets are. Annoying.../sigh. It's really the only thing that didn't work out with the NBN install.

    I have ethernet sockets everywhere throughout the house though, can I use these in some way?
     
    Dark Heart likes this.
  8. OP
    OP
    Dark Heart

    Dark Heart Member

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    Previously we were on "naked" ADSL - is that enough of a disconnection? Or do you mean a disconnection inside the house? There is a "krone block" in the same cupboard which has an ADSL filter next to it. That's where we used to plug the DSL model to ... Apologies for the ignorance.
     
  9. caspian

    caspian Member

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    disconnect inside the house. you don't need the ATA trying to energise the line all the way to the old Telstra exchange, even if it's disconnected there.

    effectively the in-house wiring will just be an extension cord from the router's voice port to the wall socket.
     
  10. OP
    OP
    Dark Heart

    Dark Heart Member

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    Would that require a licensed cabler?
     
  11. evilasdeath

    evilasdeath Member

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    It really depends how your house is currently wired, if you have a central splitter that has sockets on it you can unplug them which your allowed to do, however if your house is star wired like most then yes.

    The simpler option is dont use house wiring at all and just use a cord less handset and plug it to your ata directly then it never touchs house.
     
  12. Sphinx

    Sphinx Member

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    If you don't have a wired network in your home, you could just get a cordless voip phone with a base station that plugs into any data port on your modem/router while the handsets live around the house.
    Configure it with a web-interface, and can add extra handsets as needed.

    e.g: https://www.devicedeal.com.au/VOIP-Cordless-IP-Phone

    upload_2020-9-15_19-50-55.png
     
    Last edited: Sep 15, 2020
  13. OP
    OP
    Dark Heart

    Dark Heart Member

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    This is the option I've gone with as I don't want to spend any more time on this issue. Just bought a cheap(ish) cordless phone.
     
  14. MR CHILLED

    MR CHILLED D'oh!

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    This is what I do however I now have the main unit stuck in the study which is not where I want it.
     
  15. caspian

    caspian Member

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    that is the simplest solution. get a phone with multiple handsets if need be.

    my understanding is yes, because the cabling is in-wall.
     
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  16. Pugs

    Pugs Member

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    Correct ⭐ for you
     
  17. callan

    callan Member

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    I see the OP has gone with a VoIP handset which is great. A caution, though had the OP chosen to use the house wiring, and have it isolated from the POTS connection to the street.

    Most VoIP ATA's only have a ring equivalence of 1, which means that only 1 phone can be connected. Any more and, whilst you can dial out, your phones won't ring on incoming calls. Curiously the Cisco 122 ATA has a RE of 5 (!).
    Obviously this does not apply if using a base-station and multiple wireless handsets :)

    Just something to file away.
     
  18. caspian

    caspian Member

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    interestingly, the device pictured above (although there are several devices on the page linked to) is both a SIP phone which would connect to an ethernet port on the RG, but it also has an FXO failover connection which won't work on a disconnected POTS line... but it possibly might if you connected it to the voice port on the RG! would be a nice experiment to see if that actually worked. very complicated way of making a phone call though.
     
  19. Agg

    Agg Lord of the Pings

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    I've read this thread but have some questions. We have recently found ourselves in a similar situation. We've had FTTN NBN for a couple of years with the analogue phone working on the other line, but now it has been turned off. Mobile reception is basically nonexistant at our rural-ish property so we need a working "landline" number so the school can ring us if the kids hurt themselves or something. Our modem/router does not have the RJ-11 port needed to magically turn our existing analogue phone base into a VOIP phone.

    Wifey is keen to get this resolved this weekend. I had a look at Officeworks and Harvey Norman and all they have are "NBN Ready" phones which seems to just mean they plug into the RJ-11 port (which we don't have) on your router. Getting a proper RJ-45 IP phone seems to be crazy expensive and fairly limited in options. So I guess we want a gadget which has RJ-11 on one side and RJ-45 on the other - which will let us plug in our existing cordless phone base now, and work with any normal analogue phone we buy in future. Any recommendations on those available from big box type stores?

    Also, once the physical networking is set up, how do we assign a phone number to that device on our network?
     
  20. evilasdeath

    evilasdeath Member

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    You might not find a stand alone ATA at a big box store they are a little more niche as more used commerically not in the SOHO enviroment.

    Pick the cheapest voip router and just turn the wifi/routing etc off.

    Else online is only way.
     

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