Originally Posted by
xgjunkie
My understanding is that if engine parameters dont change then no data other than a handshake occurs. That handshake essentially has no data.
The pings carry the ID of the sender - that is how INMARSAT know what to do with the ping, reject it or accept it and what level of service it should get. If you get a cell phone and turn it on - the first thing it does is start pinging the networks with its IMEI - the networks that do not service that phone take no notice the ones that do respond. So in this case no ACARS data but electronic identity data.