Voice over Internet Protocol carrier Vonage and long-standing telephone carrier Verizon will lock legal horns in court this June. The suit, filed by Verizon under the claim that Vonage had violated several of its patents, specifically the technology Vonage uses to connect calls from Internet Protocol-based phones to traditionally networked phones.

Vonage has denied any form of patent violation and cites that most of its technologies are standards-based as well as widely available throughout its industry. In a sample cited over on ZDNet's coverage, Vonage has stated that it used voice gateways available from Cisco to route voice traffic over the Internet and connect its phone calls to regular phone networks.

Vonage could face both monetary damages as well as an injunction which could shut down its service until a non-violating workaround was discovered and implemented. A shutdown could interrupt service for Vonage's customer base, which numbers around two million subscribers.

The suit comes at a time when Vonage, despite heavy marketing efforts, hasn't been able to add as many new subscribers as the growth rate found among its cable operator components. Vonage gained an additional 166,000 new subscribers for its service in the fourth quarter, down from 204,591 new subscribers in the third quarter and 256,000 new subscribers in the second quarter of 2006. The firm is looking to offer additional services and has recently struck a deal with Earthlink to resell wireless broadband in various cities as well as stated that it will begin selling dual-mode handsets capable of sending and receiving both Internet-based as well as cell phone calls.