When you sign up for the NBN in search of a broadband boost, telcos don't tend to mention the hassles you might have with your home phone line.

Whether we use it every day or ignore it completely, our home phone service is something Australians generally take for granted. By now most people realise that switching to the NBN means your home phone will no longer work during a power outage, unless you opt for the battery backup service, but we're not told about the other complications.

My friend Michael is a perfect example, he got caught up in Optus' push to quickly shift HFC cable customers across to the NBN but, despite the shabby treatment, decided to stick with the telco.

After threatening to cut off his home phone and broadband if he didn't move to the NBN, Optus' call centre staff kept insisting that "nothing will change, everything will be exactly the same". Michael soon found out that wasn't the case.

Firstly, Michael discovered that moving from Optus cable to NBN cable meant losing his long-standing "Optus TV featuring Foxtel" legacy pay TV service, which has left him weighing up the alternatives and contemplating a Fetch TV Mighty PVR. This week Optus has finally enabled the multi-room features linking the Mighty PVR in your lounge room to the Mini set-top box in your bedroom.

Then, at the last minute, Optus also told Michael that it was his responsibility to pay someone to rewire his home phone so it would work after the NBN switchover – an issue which wasn't raised at any point during the Optus sign-up process or mentioned in the paperwork.

Not so Plug and Play

The trouble is that Michael has his new NBN wall socket, NBN NTD modem and Optus NBN Gateway router installed in the spare bedroom alongside his computer. Meanwhile his home phone is plugged into a wall socket in the kitchen. This would be a common set-up across Australia but unfortunately it causes complications when switching your home across to the new national network.

The problem is that once you're on the NBN your home phone needs to plug into the NBN Gateway router supplied by your Retail Service Provider (RSP) – in Optus' case a Sagemcom F@ST 3864 Gateway.

If you want to keep using the telephone socket in another room then you need to rewire that socket to connect to the Optus Gateway, but Optus doesn't always tell you about this. Alternatively you could plug a cordless base station into the Gateway and keep a second cordless phone in the kitchen but, like Michael, you might not want a phone in the spare bedroom if guests sometimes sleep in there.

According to Optus; "Customers only require a professional install with NBN when the end user is unable to complete the installation themselves or would like to continue to utilise their existing phone jacks, as opposed to a connection via the modem."

This wasn't explained to Michael. He was initially told that his home would require a "professional installation" – although exactly what this meant wasn't explained – and Optus would waive the cost. Then he received conflicting messages from Optus telling him that his home was designated as "self-install", so they posted him the Gateway and expected him to plug it into the new NBN modem himself.

Of course this didn't sort out the phone wiring, so Michael was told to pay someone to fix it or else he wouldn't be able to use the phone socket in the kitchen. It's not a one-off issue, as two of Michael's friends who've signed up for Optus cable have been through the exact same situation.

Once the phone was up and running Michael discovered that when people called his home an automated Optus service answered the phone after six rings to announce "The person you have called is not available" – not leaving enough time for his home answering machine to kick in. It even happens when he's on the phone, rather than the caller hearing an engaged signal. He also found that outgoing Caller ID was disabled. He's in the middle of another round of calls to Optus to sort out these issues.

Ask questions

If you're getting hooked up to the NBN, make sure you ask about your home phone arrangement upfront – explaining the exact location of your current telephone sockets and the preferred location of your new NBN wall socket. It's also important to discuss issues such as security alarms, medical alarms and other complications.

If the phone and NBN sockets are not alongside each other you'll need to rewire your telephone sockets, so make sure you clarify who will foot the bill for this work. If you're paying someone, you might consider getting them to also run Ethernet cables from your Gateway to behind your television.

In Optus' defence most telcos seem to be the same, treating the home phone as an afterthought during an NBN migration even though it's still considered an essential service by many Australians. Whichever internet provider you choose, you need to ask questions about the home phone service rather than assuming everything will take care of itself.

Telstra says; "To have a home phone connected in a different area of the house, customers will need some rewiring done so their existing phone sockets will work on the NBN. Alternatively, they can use a wireless handset that connects back to a base hub plugged in to the modem. The Telstra sales teams are trained to tell customers about this before they migrate to the NBN and it is also included in the welcome letter and modem install guides we give to customers."

"Telstra will arrange rewiring of existing phone sockets for customers with a voice-only service, customers with priority assist services and senior concession card holders at no additional cost. Customers on a bundle can choose to order a Telstra technician to professionally rewire their existing phone sockets as well as setting up their new modem and home phones for a fee of $240."

Listen up

The fact is that all NBN home voice services are actually Voice over IP, using the Gateway from your telco as the VoIP adaptor. NBN grants all Retail Service Providers 200 kbps per customer to use for this home VoIP service, but there are no rules as to how the RSPs run their VoIP networks and whether they offer Quality of Service to protect voice calls against interference from other internet traffic.  Michael has already experience several call dropouts.

Of course many tech-savvy Australians already take advantage of VoIP at home, plugging their handset into a standalone VoIP box or a VoIP-enabled router like the FritzBox 4790. Unfortunately most telcos won't let you run your new NBN home phone service via your own Gateway. They refuse to hand over the VoIP login details to configure your own gear, so you're forced to stick with the teclo's Gateway in order to use the phone.

This has resulted in a lot of unhappy Optus NBN customers who would prefer to ditch Optus' mediocre Sagemcom F@ST 3864 Gateway in favour of something better. Telstra NBN customers face the same restrictions, forcing them to stick with the Telstra-issued Sagemcom F@st 5355 Gateway if they want to use the home phone service.

The situation makes a mockery of the push to sell high-end NBN-ready Gateways over the last few years, if you need to plug your expensive Gateway into the budget Gateway foisted on you by your telco.

Your mileage may vary depending on your choice of Retail Service Provider. It appears that some progressive RSPs are prepared to hand over the NBN VoIP login details, although they might also let you use their own VoIP service with any Gateway.

The moral of the story is don't assume it will be smooth sailing when you move your home phone across to the NBN. Have you made the switch? Did you run into trouble?