The Software Freedom Law Center on Friday filed suit against Verizon for allegedly violating free software's General Public License through its fiber-optic Internet and television service, FiOS.

Verizon is a corporate giant compared with the targets of three pervious enforcement actions in the United States. In September, director Eben Moglen filed suit against Monsoon Media in a case that was settled out of court Oct. 30. On Nov. 19, the center filed suits against High Gain Antennas and Xterasys for violations of the GPL.

All four targets of the suits are users of BusyBox, a set of tools and utilities frequently included with Linux when it's embedded in a hardware device. It was issued as GPL 2.0 code by the two independent developers who wrote it.

Monsoon used BusyBox in its Hava TV products. High Gain uses BusyBox in some of its multidirectional antennas. Xterasys included BusyBox in unspecified products, but it produces broadband and Wi-Fi boosters, Ethernet cards, and Bluetooth transmitters.

Verizon provides an Actiontec MI424WR wireless router to its FiOS customers to manage customer Internet traffic at the customer's site. "This router contains BusyBox, and under the terms of the GPL, Verizon is obligated to provide the source code of BusyBox to recipients of the device," said a prepared statement issued by the center upon filing the suit.

Verizon has been contacted by the Software Freedom Law Center but "continues to distribute BusyBox illegally without source code," the statement said.

In a previous case, the center left less than 30 days between notifying a BusyBox user of his GPL violation and filing suit, according to a law student, Luis Villa, in his blog. He is a second-year student at Columbia Law School.

"Because Verizon chose not to respond to our concerns, we had no choice but to file a lawsuit to ensure that they comply with the GPL," said Dan Ravicher, SFLC's legal director in the statement.

The SFLC has not fought a case through the courts on behalf of the GPL in North America yet. Doing so would establish that the GPL is license that can be enforced on behalf of free and open source code, such as Linux, Samba, and BusyBox. In the Monsoon settlement, Monsoon agreed to make the BusyBox source code available to customers, and BusyBox writers Erick Andersen and Rob Landley received a financial settlement for Monsoon's distribution of BusyBox.