For many years we have supported a couple of Ultra runs with
Amateur Radio.? Many of the aid stations have no cell coverage and
we
used to send info about each runner to start/finish net control via
voice which when you have 200 runners is really tedious and time
consuming.? The course is very rugged and we keep track of the runners
to keep them safe.
A few years ago my son-in-law and his brother built an app using
FLAMP
using a cell phone or tablet for input of each runner.? After you have
input several runners into the app all you do is hit the PTT on your
radio, hold the microphone by the tablet/cell phone and data for that
batch of runners is sent.? It is amazing how robust the transmissions
are.? Many times it just sounds like open squelch but the data still
gets through even if the microphone of the receiving
computer is 15 feet away in an echoing trailer!!...
So you don't need a digi-rig, or other interface box, to do short digital text messaging over the air.