Telegram?

No, not the app.  Actual, you know, telegrams.  Hard to believe, but they still exist and you can still send them.  Weirdly, there is a legal reason in certain cases why you might, namely to leave an official record for later legal reference.  Anyway, here's an old article at Atlas Obscura, and the actual

send-a-telegram web site.  Prices start at $30, so if you get a message at all from me it'll probably be a text or email.

No real tag for this one, but because Morse code is peripherally connected, so I'll file it under 'radio'.