Opening fixed-line telephone bills can prompt nasty shocks for chatty householders.

As they scan their bills to check that their debts have not been enhanced by any premium rate line misadventures, the talkative amongst us can take one of two actions if they want to cut their call costs: either stop keeping in touch with friends and family or consider switching to a new phone service.

Assuming that the first suggestion is not really a viable option, it may be time to consider the claims of the dozens of telecoms companies that are trying to dent Eircom's 80 per cent share of the residential landline market.

Up to 40 per cent can be knocked off monthly telephone bills, according to Eircom's competitors.

Lately, Eircom representatives have been knocking on doors, imploring customers to see how much they can save by moving from its regular billing system to Talktime, its new range of package deals, where consumers pay a fixed monthly sum for line rental plus a number of inclusive call minutes.

But it will make sense for any householders who take the time to examine how they can cut their call costs to also cast their eye over rival offers.

The good news is that switching landline provider is now a much more desirable option thanks to the advent of single billing, which means that the 1.6 million phones in the Republic are no longer tied to Eircom for line rental.

"Free at last!" is how Esat BT gleefully phrases it. On Monday, it became the latest company to set up a single billing service in an attempt to sweep up Eircom customers.

Smart Telecom, Gaelic Telecom and UTV Talk also offer single billing.

Up until June, Eircom's competitors had to use a system known as carrier pre-selection (CPS), where householders are billed by Eircom for line rental but by the rival company for the cost of the calls they make.

Savings could still be made but consumers were faced with the inconvenience of having to pay two separate bills.

Now disaffected Eircom customers can shun the company completely and figures from the Commission for Communications Regulation (ComReg) show that a "promising" 17,000 consumers did exactly that in the first month in which single billing was available.

The bad news for the many thousands more consumers who would like to switch landline providers, but also want an easy life, is that deciphering which company offers the best value is tricky, with much depending on individual call patterns.

The move toward offering mobile-style package deals with inclusive call minutes and/or free calls rather than simply charging on a per-minute basis makes it even more complex for consumers to work out which operator will be the best for them.

For example, Eircom's cheapest Talktime package costs €29.99 a month. This includes line rental of €24.18 a month and 300 minutes worth of off-peak local or national calls and 120 minutes of "call a friend" calls, again off-peak.

Talktime customers can then pay extra if they want a bundle of off-peak calls to mobiles for a fixed rate i.e. 30 minutes' worth of such calls costs €4.20 a month or 14 cent per minute.

But none of the inclusive calls in the Talktime packages are for peak hours, so a person who uses their phone heavily during the day will not benefit quite so much.

Daytime local and national calls under Eircom's Talktime packages cost 4-4.8c per minute, with the highest 4.8c charges applied to the lowest value €29.99 package. In other words, customers who use their phones the least are charged more per minute.

These rates are lower than those charged to Eircom customers who have not yet signed up to Talktime but, for the daytime user, landline providers such as Esat BT, Smart Telecom and Gaelic Telecom offer a better deal.

Take Esat BT's Advantage service, where the only fixed monthly cost is €24.18 for line rental. There are no free call minutes but peak-time national calls cost just 3.8c per minute compared to 8.17c per minute under Eircom's standard service.

For consumers who want to avoid the confusion of a package deal, Esat's Advantage service is the straightforward way to get the lowest daytime rate for national calls. Only the most expensive of Gaelic Telecom's package deals offers as low a rate for these calls.

In addition, the cost of calling a mobile phone from the landline is cheaper at Esat BT than at Eircom, while evening and weekend calls to 30 countries cost just 8c per minute. This significantly undercuts Eircom's international rates.

Gaelic Telecom, which is a partnership between Access Telecom and the GAA, charges up to 20 per cent less per minute when compared to Eircom's standard rates.

Its package deals are structured in the same way as Eircom's but, in many instances, include a higher number of off-peak call minutes for a lower price as well as cheaper peak rates. Only the cost of off-peak calls to mobiles is slightly more expensive.

Meanwhile, Smart Telecom and UTV Talk do not bundle together calls and rental in a package deal. Their call rates are, however, cheaper on average than Eircom's.

Smart Telecom, the first provider to introduce single billing, is the joint cheapest provider for daytime local calls (alongside Esat BT).

In a move designed to whip up further business, the company is running a scheme called "Smart to Smart", under which telephone calls of less than 60 minutes' duration between all residential Smart customers are free.

At UTV Talk, consumers don't have to wait for their friends to make the same move as them to benefit from free calls.

All local, national and UK calls made at off-peak times that last less than an hour are free. But the downside is that UTV Talk's daytime rates are higher than at Smart or Esat BT.

Under Esat BT's Advantage Plus, consumers can make fixed-line local and national calls of up to 60 minutes' duration at all times of the day for €25.

This minimum monthly cost condition means that Advantage Plus will not be suitable for people who prefer face-to-face conversations, but it could prove extremely good value for phone addicts determined not to form expensive mobile habits.

Once consumers have selected the company and service that best suits their talking needs, most of the hard work is done.

Those with the itch to switch should be able to keep their telephone number, avoid signing 12-month contracts in most cases and complete the move without any break in their fixed-line connection to the outside world.

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