PTT Radio systems - A bast from the past... & future?

Part 2

Part 3

I will also note that I am looking into building a interface for 4G POC on our ASL/Asterisk
But don’t get to excited, these things take me a long time and often I give up for long periods.
I have ordered some 4G hardware for the task.
If you are not aware (many in the US), zello is a example of PTT Over Cellular. POC
But who wants to subscribe to a service for personal use, right ?

Perhaps one of you who is working on this now would like a beta man ?

But looking for existing attempts is how I stumbled on these videos. A little history in there. Interesting.