When you see a photo of someone using a brick-size cell phone, back in the day, that's an example of 1G (first-generation) mobile technology.
In the 1990s, things got really high tech as text messaging was added to voice with 2G.
In the 2000s, 3G technology brought mobile data, or the ability to email and browse the web from your phone.
And in the 2010s came 4G, with boosted bandwidth for a world of "apps" and high-definition video streaming.
Now comes 5G, with fifth-generation mobile networks already being rolled out in the US, Spain, Germany, Italy, South Korea, Australia - and now New Zealand, where Vodafone has got at least a six-month jump on its rivals with a 5G rollout that will begin in December.
"4G has pretty good data capabilities, but 5G takes it to a whole new level. It's about massive bandwidth, very low latency, quick response times, but also the ability to do IoT (the Internet of Things), higher capacity data applications for industry, gaming and all sorts of things, so it's really a massive leap on 4G."
Baird says with Vodafone's initial 5G rollout, we'll see speeds of around 300 megabits per second.
In lay terms, just know that that's faster than most residential UFB fibre connections.
Or as the Wall Street Journal tech reviewer Joanna Stern colourfully put it after trialling the technology in the US on a Samsung Galaxy 10 smartphone: "5G is fasten-your-seat-belt fast … I downloaded the whole new season of 'Stranger Things' from Netflix in 34 seconds."
But 5G isn't just about raw bandwidth, or speed.
4G and earlier mobile technologies do have a greater "latency" or slight lag with two-way connections (think a video call or multiplayer gaming) compared to a good landline broadband connection.
But 5G can take latency down to just a few milliseconds (thousandths of a second), meaning it can go toe-to-toe with fibre as the best broadband solution.
Almost zero latency for two-way connections coupled with massive bandwidth allows for jaw-dropping breakthroughs. It's why 5G has already been used for remote surgery, and why Vodafone NZ was able to demo the technology with a hologram call.
But it also has more meat-and-potatoes benefits, which we'll see as it facilitates the expansion of services like fixed wireless - or using a mobile network to supply broadband to a home or business as a total replacement for a landline.
Fixed wireless is around today, but 5G will let you use it for full-blooded internet, and relatively modest data caps should be replaced by more generous allowances and even some unlimited data deals.
5G also has a raft of network smarts that make it a better choice for everything from connecting various smart gadgets to the internet to specialist apps for areas like health, education and emergency services, which the Herald will be exploring over the coming weeks.
That's helped Vodafone land a blue-chip roster of early 5G customers including the NZ Police, BNZ, Auckland's Rescue Helicopter and Waste Management.
Applications are in the works for everything from triage units in the field able to send complex data about a patient to a hospital in real-time to smart bins that can send alerts when they're full.
How did Vodafone NZ manage to get a jump on its opposition, especially with the government yet to set a date for its 5G spectrum action (which is expected to see 80 to 100MHz of 5G-friendly airwaves put on the block)?
Baird explains that Vodafone was in the unique situation (in NZ) of already having some 5G spectrum in its pocket, thanks to its earlier acquisition of TelstraClear, which saw it inherit 58MHz of 5G-capable spectrum in the 3.5GHz band.
And it doesn't hurt that while Huawei (used by rivals) has been blocked from a 5G upgrade by the GCSB, Vodafone NZ's long-time technology partner Nokia Networks has been approved.
And for those who're worried Vodafone's early 5G rollout is just about hype, Baird reels off the numbers: 100 cell sites in Auckland, Wellington, Christchurch and Queenstown will be upgraded to 5G by December, plus 20 COWS (cell sites on wheels, used for boosting mobile reception at special events or holiday hotspots in peak season).
Over the next three years, 1400 cell sites will be upgraded to 5G for 94 per cent coverage of the country by population.
To connect to a 5G mobile network, you do need a smartphone or tablet or other device that supports 5G. Here, we've seen the floodgates start to open. Samsung and Huawei have already added 5G support to their top-shelf smartphones, and Apple recently bought Intel's 5G business for US$1 billion, underlining its seriousness about the technology (there's no official timeline for a 5G iPhone, but pundits are talking about July or August next year).
Baird says they'll be no extra charge for using 5G at launch if you're already a Vodafone customer by December.
Do I have to worry about 5G and health?
Nope. Not at all.
While some in the conspiracy theory crowd have latched onto 5G, experts say it's safe.
As scientist Dr Michelle Dickinson explained in one of her recent Herald columns, "The frequencies we refer to in mobile phone technology are all radio signals, and often referred to as RF or Radiofrequency radiation. For most people, anything with the word radiation in it sounds scary. It's not as intimidating as it might seem though - the word just means the emission of energy from any source.
Dickinson explained that emissions fall into two broad categories: ionising, which have enough energy to harm DNA and cause cancer, and non-ionising, which just don't have enough energy to do any harm.
Emissions from radios, mobile phones, phone towers and Wi-Fi routers are non-ionising.
Numerous long-term studies have backed up this science, as have health statistics collected by the UN's World Health Organisation and our own Department of Health.
At this point, the social media mob will be saying, "Ah - but 5G is much more powerful than 4G!"
To this, Dr Dickinson says, "As the frequency goes up, the depth of penetration into biological tissues goes down. This means that 5G is even less likely to penetrate the body than the current technology that we use, so there's no need to invest in a new tinfoil hat."
