Caps on the price of sending an SMS from a mobile phone while abroad came a step closer Wednesday, when the European Commission launched a two-month public consultation into its rules on mobile phone roaming charges.

Mobile phone manufacturers, network operators and consumer groups have been invited to submit comments about the effectiveness of the regulation on roaming charges for voice calls that came into force last year.

As well as seeking general feedback on the impact of the European Union law, the Commission also asked stakeholders whether regulation is necessary for data roaming services and SMS in light of current retail prices and market developments.

The results of the consultation will influence the Commission's decision whether or not to extend the existing roaming law to include data and SMS roaming charges.

A report published by the European Regulators Group in January showed that on average across the E.U., users had to pay ¬5.24 per megabyte of data and ¬0.29 for an SMS sent while roaming in the third quarter of 2007. The Commission suspects that this is disproportionately high compared to data and SMS prices when sent from a person's home country.

The existing roaming law requires operators to offer customers a "Eurotariff" for voice calls when roaming in other E.U. member states, and introduced ceilings of ¬0.49 per minute for making calls and ¬0.24 per minute for receiving calls. These will decrease to ¬0.46 and ¬0.22 respectively on Aug. 30, and to ¬0.43 and ¬0.19 on Aug. 30, 2009.

The roaming regulation is limited to voice calls and expires on June 30, 2010 unless the European Parliament and the Council decide, on the basis of a proposal from the European Commission, to extend it beyond this date.