Washington ? The Supreme Court said Friday it would intervene in a patent dispute between giants Microsoft Corp. and AT&T Corp. about Windows programs distributed overseas.

An appeals court ruled that Microsoft had infringed on an AT&T patent for a type of speech-coding technology.

The outcome could be worth more than $1 billion to Microsoft if the justices find that the lower court ruling improperly extended U.S. patent protections to overseas transactions, said Dennis Crouch, a visiting law professor at Boston University.

Microsoft lawyers claimed the ruling by the U.S. Court of Appeals for the Federal Circuit in favor of AT&T “threatens to impose massive liability on U.S. software companies” and could prompt companies to move their research facilities out of the country.

AT&T lawyers said that the ruling only protected its patent, which covers a program with a “speech code” that digitizes speech.