Earlier this month we reported about the transition of the United States ATC system to a National Single Data Authority (NSDA). https://ops.group/blog/cpdlc-for-us-airspace-the-implementation-process/
The initial phase of this process is scheduled to start this weekend on 22Oct at 0330Z with a single CPDLC logon ID for domestic US airspace (KUSA) and ATC issuing departure clearances using CPDLC.
You can read more details about Controller-Pilot Data Link Communication–Departure Clearance (CPDLC-DCL), general procedures for logging on/notifying, loading the flight plan, receiving the CPDLC-DCL, responding to the CPDLC-DCL message, and disconnecting/logging off here:
Get the famous weekly 
