The case dates back to December 2002 when Chamberlain Inc. sued Skylink Technologies over Skylink's universal remote transmitter - a device that could open, among other things, Chamberlain's "Security+ garage door opener system".
Chamberlain argued that, because the device circumvented a "rolling code" security function contained in Chamberlain's product, Skylink was in breach of the DMCA. The law makes it an offence to circumvent technological measures aimed at restricting access to copyrighted works.
The case was seen by many as highlighting the very broad nature of the DMCA, because Chamberlain's case was based on the mere fact that Skylink's device could open its customers' garage doors. On most other occasions that the DMCA has been cited in court, it has been on the grounds that the device in dispute allowed the copying or reading of copyrighted works.
On Tuesday the US Court of Appeals for the Federal Circuit restricted the scope of the legislation, unanimously upholding a November ruling by District Court Judge Rebecca Pallmeyer that, "a homeowner has a legitimate expectation that he or she will be able to access the garage even if the original transmitter is misplaced or malfunctions."
Giving the opinion of the court Judge Arthur Gajarsa wrote, "The essence of the DMCA's anti-circumvention provisions is that [they] establish causes of action for liability. They do not establish a new property right."
The court found that, to be successful in a claim under the Act, Chamberlain must show a relationship between the alleged circumvention and the use of copyrighted software contained in its garage door opener. Judge Gajarsa explained:
"A copyright owner seeking to impose liability on an accused trafficker must demonstrate that the trafficker's device enables either copyright infringement or a prohibited circumvention. Here, the District Court correctly ruled that Chamberlain pled no connection between unauthorised use of its copyrighted software and Skylink's accused transmitter."
In effect, said the court, even though Skylink's transmitter circumvented the Chamberlain's chip, it did not actually infringe on Chamberlain's copyright and therefore there was no claim under the DMCA.
Chamberlain and Skylink have yet to comment on the ruling.