In the never ending game of patent battles the latest to be hit by a lawsuit is American carriers AT&T and T-Mobile USA, with both being sued by Swiss company, Starhome GmbH of Zurich over voice mail roaming access patens.

According to an article on Reuters, the lawsuit was files in the Delaware federal court last week and the Swiss company is looking to stop T-Mobile USA Inc and AT&T Mobility LCC from offering some international roaming services and is asking for unspecified damages.

According to court documentation, Starhome makes products to improve international roaming on mobile phones and provides 178 mobile handset companies globally and the lawsuit is pertaining to two patens issued in 2005 and 2007 to Starhome, and the lawsuit was brought against Roamware Inc.

The Starhome patens cover services which enable phone subscribers to use the same “sort codes” they use while at home to access voice mail when overseas without the need to dial international calling codes along with enabling car rental and airline firms to offer the customer access to local toll-free numbers when abroad.