Secretary of State Tom Schedler says the new machines will function much like the older ones, but feature newer, crisper screens and be easy to set up.
An unidentified Foreign Ministry spokesman in Pyongyang said Saturday that the U.S. would face unspecified "grave consequences" if it rejects its proposal for the joint investigation.
The official said the State Department shut down the email late on Friday as part of a scheduled outage of some of its Internet-linked systems to make security improvements to its main unclassified computer network.
Fazio Mechanical Services Inc., of Sharpsburg, has issued a statement saying it was the victim of a "sophisticated cyberattack operation" that is linked to the U.S. Secret Service investigation of the Target data breach.