What is data linking and how it is being used already?
Data link can be compared to e-mail; it allows pilots and controllers to send messages to each other. The messages are preformatted and standardised, making composing and reading messages easy. To understand the advantages you can think of e-mail, uninterruptive, clearly readable, retrievable, usable when the phone is busy. But you can also understand the drawbacks: not as immediate as voice, cannot convey emotion (a sense of urgency), requires visual attention, etc. Today data link for ATC is used to send airport information, departure clearances, oceanic clearances, direct routes, NSSR codes and to tranfer an aircraft from one sector/centre to another. They are not very urgent, so they were ideal candidates for data link.
