It frustrates me how much disinformation is floating around about phone system compatibility on the NBN – much of it being driven by greed. There are many horror stories around including from a company I occasionally do work for that converted to the NBN. They were told their existing phone system wasn’t compatible and had to be replaced. After this had occurred they asked me to try to connect up another phone for them because they didn’t trust the company that installed the phone system and I could see why – it was a complete mess. It should have been installed in the rack and tailed out properly rather than reuse the messy Krone frame of the old system. They were charged $7,000 for this system that does an identical job to the system they had.
To clarify: virtually every phone system from the last 15-20 years is compatible with the NBN as long as it dials using tones. At the moment it is only analogue lines that are affected by the NBN. If you have any form of digital line such as ISDN2 or ISDN10/20/30 or an Optus Multiline then they are exempt from the copper cut off for the time being because there are no equivalent products available.
To enable compatibility with the NBN, all you have to do is add a small and relatively cheap device called an Analogue Telephone Adapter (ATA). The ATA converts a line delivered over the Internet back to analogue so it can be connected to your phone system. These ATA’s range from a single port upwards. For business customers 4-port and 8-port ones are most commonly used from a variety of manufacturers.
You simply Port your numbers across to the new retailer, they provide the credentials to be programmed into the ATA’s and your service will be virtually the same as it was except with potentially lower bills.
If you have a more advanced phone system that can be equipped with a card or licensed up to enable a SIP trunk to be provisioned then I refer to that as being natively compatible with NBN because no other converter like an ATA is required.
Unfortunately there are a few changes that are required for NBN such as updating EFTPOS machines, retrofitting security systems and potentially buying a new router but there is no reason why most of the existing phone systems need to be replaced. If you decide to upgrade, do it because you choose to and will gain some valuable new features – not because your supposedly trusted advisor tells you that you have to.