It's fair to say Hartnett's credentials as a Munster fan, a mild obsession he squeezes in around his job as head of worldwide sales for Palm, are not in doubt. The California-based Limerick man has been jetting back and forth from the American west coast to follow the province's journey through this year's Heineken Cup, culminating in last Sunday's semi-final victory over domestic rivals Leinster.

Despite having toasted the victory in customary fashion with the Munster faithful, he is in fine fettle. He zips through the slideshow of pictures and video clips on his Palm Treo on the Monday morning after the game, prior to disposing of the last engagements of what has been a hectic weekend trip. Following the interview he has scheduled a meeting with former Parthus chief executive Brian Long, with whom he is a partner in venture capital firm Atlantic Bridge Ventures. While home for the weekend he also took the opportunity to have a chinwag with outgoing University of Limerick president Roger Downer, his fellow board member at UL.

Hartnett likes to keep himself busy.

Back in California he works with the American Ireland Fund and sits on an Enterprise Ireland body which helps Irish companies working in the area of wireless technology. The Atlantic Bridge and UL roles, meanwhile, are ways of both keeping in touch with home and "giving something back", he says.

Hartnett is passionate about advancing the university's cause. A former assembly line worker with PC manufacturer Wang in Limerick, he took night classes at the university to further his career. That seems to have worked out pretty well. Having worked in Ireland with a number of US technology firms, including Apple subsidiary Claris, he moved to the States to take up a job with Handspring six years ago. Handspring, founded by Palm executives, was subsequently bought out by their former employer.

As "senior vice president, worldwide sales", Hartnett now reports directly to Palm chief executive Ed Colligan and is responsible for ensuring that the phenomenal growth in the company's revenues, up 34% to $1.3bn last year, continues.

To maintain that momentum Palm needs to crack the European market. Its Treo "smart-phone" has found a willing audience among Americans. The phone, when not in use to record precious moments at Lansdowne Road or Thomond Park, combines the functions of a mobile phone and a PDA (personal digital assistant).

Treo is challenging the dominance of Research In Motion's previously all-conquering Blackberry as the handheld device of choice for trendy professionals.

Even Jack Bauer, the anti-terrorism agent played by Kiefer Sutherland in hit television series 24, uses a Palm device.

"He can do things with a Treo that we never even knew about, " Hartnett jokes.

Palm has doubled market share in the US in the past year, from 10% to 20%, and has seen its stock gain 50% over the same period. Europe, where the Treo is still virtually unknown, is the new battleground.

Hartnett sees Ireland as beach head from which to launch an assault. Palm has recently established a research and development centre in Dublin, the first time the company has ever located R&D or design functions outside the US.

"We view Ireland as a launch pad for us on a European perspective, " he says. Its Dublin site employs 30 at present but that is likely to grow if Palm is successful in establishing the Treo brand in Europe.

Palm is one of many hardware manufacturers offering a solution to a perceived need for convergence among handheld devices. The question is obvious. Who wants to carry a Blackberry, an iPod, a laptop, a PDA and a phone when you can cram most of the key functions into one device? The answer depends on which manufacturer you consult. HP has PDAs with a built-in phone, Nokia and Motorola have phones with all the functions of a PDA and Palm has feet in both camps.

Its devices aren't cheap. A Palm Treo 650 retails for over 530. That does compare favourably with competing products available on the market here. O2's XDA, combining a phone and a PDA, will set users back 509.

The price tag has not been too offputting in the US. Thanks to a tie-up with Microsoft it has an operating system that works with what most companies are using in their offices and with which most of their workers are familiar. Palm has also been helped in the market by Microsoft founder Bill Gates, who recently endorsed the Treo as the best of over 100 smart-phones using Microsoft's operating system.

Hartnett has been busy signing deals with European mobile networks including Vodafone, the only Irish network that currently sells Treos, to provide another channel to get its products into customers' hands.

The company plans several product launches tailored at the European market over the next year and, Hartnett says, an extensive advertising and marketing campaign to ensure that "by the end of this year people will recognise the Treo brand". Hartnett reckons it is inevitable that both business users and consumers will catch the smartphone bug.

ever did. The other was a Treo, " he says, ever the product evangelist.

He says the roll-out of 3G mobile networks, which can provide high-speed internet services on mobile phones, will add to both the capabilities of the phones and the expectations people have about what they can do using their mobiles.

Hartnett thinks the growth of mobile internet is "the major change that is going to happen" in technology over the coming years.

Aside from the fact that such a trend would play into a certain company's palms, Hartnett says it will also be a positive development for Irish technology firms. With his venture capital and Enterprise Ireland hats on, Hartnett gets to meet a lot of Irish entrepreneurs working in the mobile sector.

"The technology that some of these Irish companies are putting together is world class, " he says. ChangingWorlds, Aran Tech and Accuris Networks . . . in which Atlantic Bridge has invested . . . are three he cites with approval.

With so much going on in the land he left, it seems reasonable to ask whether Hartnett would consider relocating, but it seems he enjoys life in Silicon Valley a bit too much.

"I never had a plan to go there and now I don't have a plan to go back, " he says . . . except to visit his family and, naturally, to lend his support to the Munster rugby team.

Speaking of which, there is the small matter of sourcing tickets for an upcoming Heineken Cup Final in Wales to be attended to. Not a problem, he says.

"Nothing is going to keep me from going to Cardiff."

THE MAN & HIS COMPANY

Name: John Hartnett
Age: 43 Family: Married with four children
Background: Began his career at 18 in the Limerick factory of computer equipment maker Wang. Gained a degree in marketing through the Marketing Institute Of Ireland and a postgraduate qualification in finance through UL. Moved from Wang to Digital and then on to telecommunications firm AT&T in Dublin before securing a job at software company Claris as director of its international operations. Later recruited by Handspring in California and moved to take up an executive position at Palm when it acquired Handspring.

Hobbies: Rugby, formerly as a player with Young Munster and now as a supporter.

Company: Palm Industry: Manufactures handheld devices such as personal digital assistants (PDAs) and smart-phones.

Financial Information: Sales of $1.3bn and operating profit of $80m