PORTLAND (AP) — Maine-based DeLorme Publishing is digging in for a fight against a $6.2 million fine levied against it in an ongoing patent dispute.

The Portland Press Herald (http://bit.ly/1lyzJ7n ) reported DeLorme’s CEO said the firm believes it’s done nothing wrong and will appeal. The mapping company received the fine from the International Trade Commission on June 10 for violating a consent order related to a patent infringement case brought by a Virginia company.

The fine concerns DeLorme’s line of hand-held satellite communication devices, which CEO Michael Heffron says accounts for half the company’s roughly $20 million annual revenue.

Yarmouth, Maine-based DeLorme employs 75 people. BriarTek of Virginia claims DeLorme is infringing on its patent by manufacturing two-way satellite communication devices. DeLorme officials claim BriarTek’s patent is invalid. The case is in court.