Up until then, he says, short spots on Capital FM were the only marketing exercise the then nascent Carphone Warehouse operation had embarked on.
When they were on air, the phones would ring; when they were not, they would sit silent.
While his company's early dependency on paid-for media might seem like evidence of an old-fashioned reliance on traditional marketing techniques, the truth is that this CEO has an understanding of both the theoretical principles and practical needs of public relations which most corporate chiefs do not share. Even the use of the word Warehouse in the naming of the company (implying scale, as well as an ability to circumvent elements of the purchasing and selling process) suggests, he admits, an early knowledge of the importance of creating the appropriate impression with your target audience.
In the intervening 15 years, Dunstone has led Carphone Warehouse through any number of business milestones. From a starting point of 'just needing to earn a living' and having £6,000 in the bank, Dunstone built one of the most recognisable names on the UK high street, with turnover soaring from £1.5m in the firm's first full year (itself an achievement) to over £1.8bn last year. Now with 1,000 stores in 11 European markets and employing over 7,500 staff, the company floated in 2000 with a market cap of close to £2bn.
In PR terms, he is widely recognised as among the most PR-friendly of the current crop of UK business leaders. Last month he was named Business Communicator of The Year by the PRCA - the fact that last year's winner was easyGroup's ubiquitous Stelios Haji-Ioannou might lead one to expect Dunstone's profile to rise yet further. In the judging for this award, the panel were unanimously supportive of his winning it. Among them, Huntsworth Group CEO Lord Chadlington described the 39-year-old Dunstone as 'a truly remarkable young man'.
According to data supplied by Echo Research in support of that judging process, 62 per cent of Carphone's media coverage in the year 2002-2003 was positive.
A robust 50 per cent was proactive in nature, and 70 per cent was described as offensive rather than defensive.
What all these numbers tell you is that Dunstone's way of doing business is to communicate relentlessly to stakeholder groups, to use the media for every possible opportunity to deliver key messages, and to take whatever chance one can get to be positioned as a thought leader in your particular sector.
Positive media feedback
Separate data assembled by TNS Media Intelligence backs up this view - with a focus on the week our interview took place, it provided the happy statistic that three-quarters of his media cuts were positive in tone. This is of especial significance as it is in the week Carphone launched its free domestic service talktalk' in a bid to attack BT's overwhelming historic market dominance.
It is characteristic of the mild-mannered Dunstone that he does his best to attribute the PR success of Carphone to his own staff (former PR chief turned marketing director Tristia Clarke and head of PR/brand communications Vanessa Tipple) and to external PR advisers.
'I try and have the very best advisers,' he says. By way of explanation, he adds that in addition to retaining Bite Communications for a product PR brief, he also used Freud Communications on the talktalk launch and has a link with Citigate Dewe Rogerson's Tony Carlisle stretching back several years. 'At around the time of the float (in 2000), of all the advisers with their snouts in the trough, Tony had the smallest munch of them all - and has proved the most resilient from those times.'
Reflecting on how the company he leads (and still owns a minority stake in) has improved its methods of communication in the years between launch and domination, he highlights the group's stock market debut as the wake-up call that made him sharpen up his act. 'Floating the company made us professionalise our communications, certainly... I've had to learn and adapt to dealing with the press,' he says.
The anecdote he offers to underline this point is telling. It concerns himself chatting at a Number 10 reception with Tony Blair's friend and fundraising adviser Lord Levy, and being tapped for £1m for party coffers.
It ends with the story coming out in one of the Sunday newspapers' business pages as a result of a casual aside to a reporter. From anyone else, this tale would sound name-droppy, even vulgar - from Dunstone, it sounds self-deprecatory, certainly charming, even a touch vulnerable.
Anyone assuming on the basis of his emerging fame that Dunstone is game for any kind of publicity would find him keen to stress the commercial logic behind his corporate communications forays: 'I try to avoid doing publicity that isn't to do with the business. I want to avoid being a media tart just for the sake of my own ego. I don't seek publicity for its own sake and I'd never do anything like me presenting a TV programme.'
Warming to this theme, he goes on: 'You run a major risk of looking like a wanker on TV. You either look flash, or arrogant or cocky. There's also an obsession (in TV programmes) with wealth, that is just awful.'
Lest anyone interpret this as a dig at other business leaders who have a reputation as being limelight-hoggers, for finding no photo opportunity too absurd or distasteful to try, Dunstone is quick to spell out exactly who his heroes are in the corporate world.
'Branson is the master, the daddy of it all. Every PR stunt he does relates back to his businesses. His character is more comfortable with that kind of behaviour, but he has a legendary status for me,' he says.
And yet his repeated self-deprecation returns when he is asked if he could one day compare himself with Branson: 'I am not a serial entrepreneur.
I just lucked out once with Carphone Warehouse. I don't really want to do anything else.'
Apart from having a sophisticated understanding of his own PR value, he also 'gets' PR from a business point of view, and understands why certain things work and others do not. 'We punch above our weight, partly because people are obsessed with mobiles, partly because we have huge influential suppliers (Nokia et al) but we have a different role from most of the brands in our market.
We don't generate awareness for its own sake, we just convert people from one to another,' he says.
Perhaps surprisingly among the Echo data, it is suggested that more can be done publicly to underline the company commitment to the principles of CSR. Only four per cent of coverage of the company in the mainstream media is to do with this aspect of his management. This is unusual because for both internal and external reasons, it is an area in which Dunstone apparently holds sincere beliefs.
'What I've always tried to do is to develop a credo within the business.
You have to market to people internally to get them to live up to the business's ideals. We market to them and, as a result, they have great pride in working for us, we have lower staff turnover and so on.'
The main manifestation of the principles he says he has tried to foster with the company, are the 'Five Fundamental Rules of Carphone Warehouse' that, one suspects, are hardwired into the brain of everyone from the chairman (former Orange guru Hans Snook) to the shop floor. Of these, two have a clear provenance in PR and corporate communications mindsets. Rule 3 is 'always deliver what we promise. If in doubt, underpromise and overdeliver,' while Rule 5 states: 'The reputation of the whole company is in the hands of each individual.'
Dunstone nods vigorously when it is pointed out that just as the first of these is a classic description of the principle of expectation management, the second sums up the need for integrating communications, marketing, product development and countless other business functions into a seamless thought process. 'Exactly,' he says. 'But the reason we have those rules is that things have gone wrong in the past. When things have gone wrong, that has led to the creation of the rules.' (The others, out of interest, all pertain to treating customers properly).
If one were to try to isolate the factor that makes Dunstone a serious contender for pre-eminent current business communicator it would have to be the nonchalant air with which he seems to grasp reputational concerns that are often beyond even the most seasoned business leader.
He says at one point, for example, in an attempt to explain the subtle positional change Carphone is currently undergoing: 'It's very easy to be the challenger - defending your position is a much harder PR position to fight. Every time the competition attacks us in the media they raise us up as credible competition. But you can't have a sustainable competitor position based simply on negativity.'
As he says this, his eyes light up and you imagine he's thinking 'more's the pity'. Because despite this realisation, his mischievous side shines through when he describes the most fun he has had yet in discharging the marcoms aspect of his responsibilities, the 'cheap trick' of poaching Maureen Lipman to front the launch of the fixed-line service last month.
Allowing major business decisions to be made with one eye for the next day's headlines? A worthy business communicator.
1989: Sets up Carphone Warehouse, aged 25
1996: Opens first stores outside the UK, in Paris and Dublin
1999: Acquires UK arm of Tandy, with 268 stores
2000: Floats the company with aim of financing growth
2003: Launches talktalk, a free domestic fixed line service