A South Korean venture firm has filed a complaint with the prosecution against Apple Inc.’s Seoul-based branch for patent infringement, sources said on Monday.

Infozone, a mobile message solution provider, said that Apple’s iMessage service, which has been installed on iPhones since June 2011, infringed on Infozone’s patents for switching data-transmission networks based on the handsets of those receiving the messages.

“If an iPhone user sends messages through iMessage to another iOS-powered user, the service will be free, like KakaoTalk.

But when the receiver is using another operating system via Samsung or LG handsets, iMessage will use paid mobile networks,” said Park Myung-heum, the head of Infozone. “This is where Apple infringed on our patent.”

He said the lawsuit would cover all of Apple’s devices, adding that Infozone decided on the move to prevent large tech firms from infringing on patents developed by the smaller players.

(hkp@heraldcorp.com)