NAT oceanic centres (Shanwick, Gander, Santa Maria, Iceland, New York) have been using it for years. The initial call at the FIR/OCA boundary usually includes a remark as to whether a flight is CPDLC/ADS equipped, but mostly this is for the benefit of the HF radio operator rather than controllers themselves.
On the kit we use here at the Prestwick OACC, (
Shanwick), the controller's display shows whether a particular aircraft has logged on, thus providing a visual indication as to comms cabability. Crews give verbal confirmation on first contact on HF if they have successfully logged on, as the radio operators don't currently have an equivalent means of identifying whether a flight has logged on for CPDLC/ADS or will continue with voice comms procedures.
Good bit of kit, once you get used to it.
