GSM phone subscribers may be without service if their phone is embedded with a SIM card from Sonera Corporation.

After 30 reported cases since late last year, Sonera Corporation has announced that it will replace 360,000 SIM cards due to a software fault which may block the card. The software default does not relate to technology developed by Sonera, the company said.

However, the defect does not affect any other features of the subscription or card in any other way, and the card can not be misused, said Sonera’s vice president Janne Vainio.

Vainio added that the risk of the card being blocked is relatively small, but the company wanted to ensure their customers subscription trouble-free operations in the future.

But to retain customer support will cost Sonera and its subcontracted manufacturer Setec millions of dollars. Both companies are currently in discussions with respect to how the costs will be divided.

"This is such a big operation, this affects such a big number of clients that simply the replacement of the cards and all logistics costs will cause significant costs," Vainio said.

Operators rely on SIM cards to identify their customers and data, such as telephone numbers and text messages, which are saved in the card’s memory.

The company said customers who have a card belonging to a series containing the software fault have been sent a personal letter advising them to replace their cards and ensuring them that their telephone numbers will remain the same.

For more information: http://www.sonera.fi/english/pressinfo/releases/EngSonera2001/2001/37.html