Wales will be the first nation in the UK to go completely digital
Viewers who have yet to convert their televisions to digital are being warned against rip-offs and cons before the analogue signal in Wales is turned off.
The Swansea, Neath and Port Talbot areas will be the first to go digital in August, with the rest of Wales following by March next year.
But it is understood 10% of main TV sets still need converting to digital.
Consumer Focus Wales warned BBC Eye on Wales potential confusion could see people being overcharged when changing.
Wales will become the first nation in the UK to go completely digital next year - via either digital terrestrial TV through an aerial - otherwise known as Freeview - or by cable or satellite dish.
On 12 August, the Kilvey Hill TV transmitter serving 132,000 homes in Swansea, Neath and Port Talbot goes digital.
Ahead of that, newspaper adverts giving consumers advice on how to switch safely will be appearing in the press this week.
But Consumer Focus Wales said it is still concerned that not everybody will be fully informed about the changes and how they can make them.
Most people will not need new equipment beyond a digital Freeview box on top of their TV
But if you do, get more than one quote, compare prices and use a reputable trader
Get a written quote for the work you want
Source: Consumer Focus Wales
Spokesman Gareth Price said the organisation was working to try to protect viewers from scams.
"We're doing some mystery shopper work, calling up aerial installers and people who sell TVs to try and see what information is about," he said.
"Trading standards officers in Dorset did a piece of work like this a few months a go and they found one case where a TV retailer was suggesting to people that they needed a £1,000 television to make the benefits of digital work for them. Just not true."
He said the bilingual newspaper adverts would be giving advice on how to change to digital.
"Most people won't need new equipment beyond a digital Freeview box on top of their TV. But if you do, get more than one quote, compare prices and use a reputable trader," he said.
"And finally get a written quote for the work you want.
"What we're trying to do is make sure that people have the correct information so they can switch safely and not be vulnerable to being ripped off."
Meanwhile, Digital UK, the body over-seeing the switchover, said it is working to ensure the TV signal in Wales is strong, despite the challenges of the country's geography.
"In parts of Wales analogue television reception isn't all that wonderful because we've got so many hills and valleys," said Emyr Hughes, the national manager for Wales.
"A lot of people have Freeview, but it has to run at low power because Ofcom won't allow us to put the power up while analogue is there because otherwise the digital signals would interfere with it.
"Now we're talking about running Freeview after switchover at higher powers - multiplying it by ten.
"So if you've got an aerial that isn't quite pointing at the transmitter or a cable that has been damaged - there will be enough signal blasting out of the transmitter after switchover to be able to deal with most of those problems.
"The new high-powered digital signals plus satellite filling in the gaps means everybody can have a really good choice of channels."
Eye On Wales is on BBC Radio Wales on 29 June at 1830 BST.