On Sun, Jan 16, 2022 at 03:46 PM, The Hempsteads wrote:

I want to have the ATU-100 send its current info (forward, reverse, power, etc.) out over a serial line to a raspberry Pi.? With that, then you could also control the atu-100 using a serial line.?

Dave, you seam to be ahead of me... I planned to do something similar now when I have a code base compile-able using free tools.
I got the idea to use this piece of software to snoop the display information using an MKR1000 Arduino and send it to a twin android over WiFi to the shack where the display is connected instead.
I can then power the ATU over the Coax and send data over WiFi to avoid more cables up and down to the attic and out through the walls.
Not exactly your planned setup but serial communication out from the ATU sent via cable, or in my case, by using an Arduino with WiFi is also a good idea.
If it would be possible to send slow RS232 over the coax it would be great but I guess it would be difficult to power the unit and send data over the same coax without also affecting receiver sensitivity and/or receiver noise level.
Just adding an arduino at the ATU might actually increase the noise level as it will be situated just next to the antenna...