ARINC stands for Aeronautical Radio, Inc. It is basically a company that creates and manages communication systems that are used in airplanes.
Think of it like this, when people fly on an airplane, they need to communicate with the people on the plane, the flight attendants, and also the people on the ground, like the air traffic controllers. These communications need to be very clear, so everybody can understand what's going on.
ARINC provides the equipment and technology to make these communications possible. They create the radios and other communication devices that are used in airplanes, so pilots and cabin crews can talk to each other during the flight.
ARINC also helps with the transfer of important data and information between airplanes and the ground. This information can be things like weather updates, flight plans, and other important data that the pilots need to know.
So, basically, ARINC plays a very important role in making sure that planes and the people on them are safe during the flight. Without their communication systems, flying would be a lot more difficult and dangerous for everyone involved.