The Collins Aerospace CMU-4000 is a data communication management unit designed to provide a minimum cost of ownership transition as the worldwide data-link system evolves from ACARS to ATN. The CMU-4000 can manage data-link communications over all three RF sub-networks (VHF, HF and SATCOM, including Iridium).
In addition to the main unit, the CMU-4000 also includes associated equipment – radios, control/display units and interfaces to other computer systems as required for specific applications. Three ground information sources communicate to and from the aircraft: air traffic services, airline operations centers and commercial service providers.
The CMU-4000 is capable of using either traditional or high-speed ACARS (AOA) over VDL Mode 2. Software upgrades will allow for concurrent ACARS (AOA) and ATN (Link2000+) over VDL Mode 2.