Audio. usually if there in the field. then in command centers it's usually Visual and Audio together.
Military Sealift Command was created in 1949.
It is not a military custom it's a military command, 'stand at ease' means to relax from the 'stand to attention' command.
Military sealift command
Change of Command.
President
Nanjing General Hospital of Nanjing Military Command was created in 1929.
European Command (U.S. Military)
Not the military chain of command, no.
The best place to find information about Mobile Command Centers is on Online Marketplaces such as Ebay or Gumtree. The seller generally lists a wide range of data on their adverts.
Hellenic Army Supreme Military Support Command's motto is 'Courage is greatness'.
In my experience in the navy, a LCDR can be in command of a mine sweeper ship, which carries up to 120 sailors. Is not a combat ship, is more like a support ship. They can also command small reserve centers or Navy Operational Support Centers (NOSC). Also, they can be in charge of an air squadron, where they are call "Air Boss".