ONLY the courageous may be willing to enter the labyrinth of mobile phone charges. Despite the popularity of mobile phones, the pricing structures of the two mobile phone companies operating in the State - Esat Digifone and Eircell - leave many users in the dark about how much, how and when they are being charged.

And the promises of the third mobile phone licence holder, Meteor, to drive down costs will not be put to the test until it finally begins operations.

This will not happen until the conclusion of a High Court challenge by its rival for the license, British mobile phone giant, Orange. It is seeking a re-evaluation of the decision by the Director of Telecommunications Regulation to opt for Meteor. The case is under way but is expected to last for several weeks.

Such is the complexity of the tariff structures used by both incumbents that mobile phone users can only guess at what they are being charged. Mr James O'Flynn, chairman of the Consumer Association's telecommunications committee is not happy with the current pricing structure. "We deplore any situation where the consumer is not presented with a clear-cut choice in simple, straightforward language," he says.

Contract Service Options: Eircell and Esat Digifone offer various rates for contract customers, pre-paid offers for non-contract customers and mobile phone purchase packages.

The majority of mobile phones are operated on a contract basis with the customer. Approval requires proof of identity, address and ability to pay. These checks mean the mobile phone company knows a customer is a good risk. As a result, mobile phone charges for contract customers are usually lower than for pre-paid mobile phone options.

Prices are usually charged according to the time of day when a call is made. Each company has different day (peak) and evening or weekend (off-peak) call rates.

Both companies include "free" calls in their package tariff options but these can be deceptive. "Options which include free calls for so many minutes cloud the issue. A straightforward per minute charge on a per second basis allows the consumer a clear cut choice," says Mr O'Flynn.

Eircell's peak hours are from 8 a.m. to 8 p.m. Monday through Friday while off-peak is charged from 8 p.m. to 8 a.m. Monday to Friday and weekends. All of the following charges include VAT.

Eircell's most basic monthly payment option is Eirtime which costs £12.10 per month with no calls included per month. Calls are charged at the highest rate of 54.45p peak and 27.23p off-peak rate per minute.

Eirtime 50 costs £24.20 per month and includes 50 minutes of calls. These calls effectively cost 48.4p per minute regardless of the calling hour. After these so-called "free" minutes, calls are charged at 36.30p peak and 18.15p off-peak per minute.

Eirtime 100 costs £36.30 per month including 100 minutes of calls meaning calls effectively cost 36.3p per minute. After these minutes are used up, calls are charged at 20.25p per minute peak and 15.13p per minute off-peak.

Eirtime 250 allows 250 minutes of calls a month for £72.50 meaning calls cost approximately 29p per minute regardless of call time. Additional calls cost 24.20p peak and 12.20p off peak per minute.

Eirtime 750 is the grand-daddy of all the options. This package includes 750 minutes of calls and a monthly rate of £145.20, meaning an effective call charge of 19.36p per minute. After that, calls are charged at 21.78p peak and 10.89p off-peak.

Eircell calls are all charged per minute, so even if you use one second of a minute, you are charged for the full minute.

Esat Digifone's peak hours are 8 a.m. to 6 p.m. Monday to Friday and 6 p.m. to 8 a.m. during the week, weekends and bank holidays.

Esat offers three main payment plans, Digilite, Digiflex and Digimax, which are selected based on perceived usage.

For direct and diverted calls, the Digilite rental plan costs £15 per month and includes £5 worth of "free" calls. Prices are 50p peak, 15p off-peak. The number of minutes available for the "free" call option is difficult to determine but if all calls are made during peak it would allow approximately 10 minutes. Off-peak only use would provide around 33 minutes. However, since prices are quoted per minute but charged per second, determining the exact number of "free" minutes per month is nearly impossible.

Digiflex is charged at £24.20 per month and includes £9.08 worth of calls. The peak charge is 24.2p and off-peak is 15.1p.

The Digimax plan also costs £24.20 per month. However, the pricing structure is more complicated. Prices for direct and diverted calls are calculated separately and there is no price difference for calls made peak or offpeak.

Direct calls are charged on a decreasing price scale: 24.2p for the first 75 minutes, 21.2p for minute 76 to 151, 18.2p for 151 to 300 and 15.1p for minute 301 and beyond.

Two benefits of Esat Digifone's service are the per second billing and the unused "free" call credits. However, your monthly bill is very difficult to calculate and it's almost impossible to determine if you have been overcharged.

Other charges for both Eircell and Esat Digifone complicate things even further. Both Eircell and Esat charge 48.4p per minute peak and off-peak for directory assistance. This service can sometimes take longer than land-line service and may therefore needlessly increase your bill.

Eircell playback or messaging service calls are charged according to particular plan ranging from 18p to 45p per minute peak and 9p to 22.5p off-peak (these numbers exclude VAT). Esat charges 15p per minute peak and off-peak for Digitext messages.

Pre-paid options: Some consumers prefer the pre-paid mobile phone option. This way they feel they know how much they will be charged each month. Unfortunately, the per minute charges on these phones is often higher than on contract options.

Eircell's Ready-to-Go starter packs range from £49 to £129. Peak and off-peak calling times differ from the contract products and range from 8 a.m. to 6 p.m. Monday to Friday (peak) and 6 p.m. to 8 a.m. Monday to Friday, weekends and bank holidays (off-peak).

Calls are charged at 80p per minute peak and 20p per minute off-peak. If more daytime calls are required, 087 users may switch to a pricing structure that charges 50p daytime, 50p evening and 20p at weekends. This is not available to 088 users.

One major disadvantage to this product is that a minimum of £20 must be credited to your account every 60 days for a continuous service.

This means a minimum expense per year of £120 no matter how little you use the phone. However, if you top up before the 60-day period expires any unused credit from your previous top-up will be carried forward.

Esat's Speakeasy product offers two tariff options. "Early Bird" calls cost 20p from 7 a.m. to 3 p.m. Monday through Friday and 75p from 3 p.m. to 7 a.m. and weekends. The "Night Owl" option charges calls at 75p from 7 a.m. to 6 p.m. Monday to Friday and 20p from 6 p.m. to 7 a.m. Monday to Friday and weekends. Two phones are offered in the package: a Panasonic G450 for £99 or a Nokia 5110 for £139.

Any way you look at it, mobile phones are still an expensive choice. The lack of clarity in pricing structures means it is extremely difficult to determine exactly what customers will pay each month.