On the Boeing 777, the system that collects aircraft performance is called a "Central Maintenance Computer" (CMC), rather than an "Airplance Condition Monitoring System" (ACMS). That difference may facilitate searching for more particlar details about the data collected by a Boeing 777 CMC. It (the CMC) appears to be a Honeywell Aerospace product, "Primus Epic." Honeywell Avionics article - Evolution of Aircraft Maintenance Systems.
Hello again Cboldt. Read your two articles. Great dtuff. Good overviews. The one thing they do not discuss is what happens if you don’t subscribe. Probably have to talk to a Boeing person to find that out. I have not seen it anywhere in my searches. But whatever happens to the data, at least we know where the pings are came from.