ACARS Server

ACARS is a complex system which consists of several software mod ules which cooperate. Depending on whether you want to simulate an airplane or a dispatch/ATC station.
ACARS by itself is mostly a transport network, used to pass short messages back and forth between aircraft and ground facilities.

It can be compared to e-mail, or even better, to cell phone text messaging. However it uses quite different technology, based on either classical VHF transmission or satellite communications.