Whoever coined the term "roaming" for GSM mobile phones did the technology a great favour, conjuring up images of carefree users roving around the world making and receiving calls as easily as if they were in their own homes.

Roaming with GSM phones may be easy, but cheap it is not. Some European cellular operators are adding as much as 50 per cent onto call charges for the privilege of roaming, while visitors to GSM countries outside the EU sometimes find themselves paying VAT twice on calls.

Roaming, whereby digital cellular telephones can make and receive calls in other countries, incurs not just the cost per call levied by whatever operator's area the phone is in, but also charges levied by the visited and home operators. The charges are typically up to 15 per cent by each operator, adding almost a third to the cost. In some cases the home operators charge even more when their customers roam abroad. Although roaming charges are levied on calls made, using a GSM mobile phone just to receive abroad is not cheap either. Callers to an Irish mobile phone here in Paris, for example, pay only for a call as far as the Eircell or Esat switches in Ireland, while the owner of the phone then pays international call rates for the rest of the call.

The charge for making a call from a roaming mobile is more complex. Local and international calls are charged at the rates set by whichever local operator the phone is using, plus roaming fees. Calls between two roaming mobiles, for instance if both are in France, are routed through Dublin, meaning the caller pays for a call to Ireland, while the recipient pays to receive a call from Ireland. Adding insult to injury, users roaming in countries outside the EU may find VAT levied on calls both by the visited operator and by the home operator. According to Ms Lorraine McCahill, product executive at Esat Digifone, EU operators only charge VAT on home bills, not on roamers. "But some eastern European countries charge VAT on roamers because they are not in the EU," she says.

But it is not all doom and gloom for roamers. New charging principles being adopted by operators and new call-routing technology should bring roaming charges down over the coming year, according to the Irish-based association of licensed GSM network operators, the GSM MoU Association. Mr Pietro Cotino, chairman of the GSM MoU's billing and accounting rapporteur group, says the current system of roaming mark-ups will disappear as operators agree to bill roaming calls at wholesale rates.

Echoing this, Eircell's roaming manager, Mr Jack Maher, says operators must all charge wholesale rates by next May, and says this system of inter-operator tariffs will allow operators to request volume discounts, reducing call charges for the customers. He does not put figures on these savings. He says French, German and Irish operators are pushing to get roaming calls billed in euros where appropriate, making bills clearer for customers.

Meanwhile, the GSM MoU is discussing a new technology called "optimal routing", which would mean calls to a mobile which is roaming need not be routed - and, crucially, charged - via its home network. Mr Cotino says this is "under discussion", and "can only work if all the operators implement it". He won't say whether this is likely within the coming year, but roamers will welcome this as it will mean significantly cheaper calls.

Another interesting development is the implementation of national roaming in Denmark and Italy. Mr Cotino, who works for Italian operator Omnitel Pronto, says the Italian regulator insisted on national roaming when awarding a third licence this summer. It means the existing operators will have to bill the third operator at wholesale rate for calls it handles. This makes it significantly easier for the third operator to enter the market, effectively giving it 100 per cent coverage by allowing its users to roam at wholesale rates on the existing networks.

The third Italian licence, like many elsewhere, is for what is called a GSM 1800 system. These networks use smaller, lowerpowered cells, suitable for highdensity coverage such as in urban areas. The special dual-band handsets which work on both the 1800 and the traditional GSM 900 networks cost more, but are becoming standard. These are particularly useful for roaming users as they provide access to more networks. Mr Maher predicts these will further push down the cost of roaming as 1800 networks will get the high-volume users.

In Ireland, the third operator, Meteor, is setting up an 1800 network, while Mr Maher says Eircell will start its own 1800 network around the year 2000.

Eoin Licken is at elicken@irish- times.ie