Brandywine Communications is taking Apple to court over alleged patent violations related to the iPhone’s voicemail software. The company is claiming, according to its filing, that Apple is using two of its patents without proper licensing.

The patents in question (5,719,922 and 6,236,717) describe a “simultaneous voice/data answering machine” system, and specifically reference retrieving voice and data messages via answering machine or computer. They also describe a system where users listen to a message while viewing related data at the same time, meaning multimedia messages.

Brandywine Communications, according to GigaOm, is facing a lawsuit of its own from Verizon over different patents. In that case, Verizon said Brandywine is “a patent holding company that is in the business of enforcing patent rights through the filing of various lawsuits.” In other words, Verizon is calling Brandywind Communications a patent troll.

The company’s lawsuit against Apple was filed in U.S. District Court in Florida.

Apple hasn’t commented on the filing.