In the latest volley of a more than three-year-old patent dispute, EasyLink Services International Corp. on Tuesday said it filed a suit against j2 Global Communications Inc., alleging that j2’s digital faxing technology infringed on its patents.

EasyLink Services, based in Norcross, Ga., operates the RapidFax messaging-service. Los Angeles-based J2, with services that include eFax, Campaigner and KeepItSafe, filed patent infringement suits against EasyLink and two other competitors in 2008 that are pending.

The new EasyLink countersuit was filed in U.S. District Court for the Northern District of Georgia.

J2 has not yet commented on the countersuit, but on Monday issued a press release expressing its satisfaction with a “Markman” order issued by a U.S. District Court judge in the Central District of California earlier this month in the patent suit against EasyLink and one of the other defendants.

A Markman hearing is a pretrial hearing in which a judge makes an initial determination about a patent dispute. J2 contends the order that came out of the March 2 hearing was in its favor.

J2 shares closed down 10 cents, or less than a percent, to $29.19 on the Nasdaq.