Hundreds of jobs are to be created from the new fibre broadband venture set up by the ESB and Vodafone.
The new venture, called Siro, will deliver fibre broadband over ESB lines to 500,000 homes and businesses in 50 regional towns over the coming three years.
The ESB and Vodafone have jointly invested €450m in the service, which will offer households speeds of up to 1,000Mbs.
The company said 60 full-time jobs would be created in Siro with 200 more construction jobs during the roll-out phase.
The new company said the first 10 towns will go live in the autumn. These are Cavan, Dundalk, Westport, Castlebar, Sligo, Carrigaline, Tralee, Navan, Letterkenny and Wexford. No pricing for the service has yet been unveiled.
Siro chief executive Sean Atkinson said approximately 25,000 households in those first towns will receive the new service by the end of the year.
Another 40 large regional towns will see the fibre network built out over the next three years. The company says it is then likely to target a further 500,000 homes and businesses in another 300 smaller regional towns. Eircom says that it is launching its own fibre-to-the-home broadband service at the same time as Siro and in the same towns.
The Siro service is different from the Government's €500m National Broadband Plan, which promises fibre broadband to remote rural areas that will not be covered by either Siro or Eircom's competing fibre broadband services.
Minister for Communications Alex White said that he expects the "physical construction" of a rural fibre network to begin in "the latter half of 2016" and that he expects it to take "between three and five years".
If it takes five years, it will be a year later than the Government's estimates when launched last year.
Both Eircom and Vodafone-ESB (Siro) say that they will bid for the National Broadband Plan's tender once it becomes available later this year.
The new Siro service is not planned for rollout in cities or urban areas, where UPC is available.
Executives say that Siro will only roll out to regional towns with at least 4,000 homes or businesses.
The service is built as a wholesale service and will be offered to local operators for resale to householders and business-owners.
UPC's chief executive, Magnus Ternsjo, said that the cable operator would consider reselling the Siro service in regional towns where UPC does not have a presence. UPC is set to launch a mobile operator in the coming months and will be pushing bundled 'quadplay' services as a key offering. A regional broadband service could enable it to widen its customer base, which currently stands at 512,000.
Construction on the new Siro fibre network began last September, delivering 1,000Mbs speeds to a test zone of 300 homes in Cavan.
The new service runs fibre along the ESB's power lines, both overhead and underground, into ordinary homes and businesses. Because it is pure fibre, there are no copper phone lines involved.
Speeds will vary from 200Mbs to 1,000Mbs, around four times the top speed of UPC and around 10 times the top speed of Eircom's current 'eFibre' service. No price has yet been set for the service, although Eircom has set a €35-per-month price on its own fibre broadband product.
ESB chief executive Pat O'Doherty declined to put a timeframe on the operation's return on the organisation's €225m investment in the scheme.