Sign wave 300Hz and just serial data short bursts.
Why............
One signal on a wind turbine panel is 24V 300Hz, it goes to the main control panel some distance away, no idea why wireless or cable isnt an option but it isnt. So I wondered if the data could be injected on top the sign wave. I dont know a huge amount about the turbine, its small and pretty old. I have absolutely zero idea why its 300Hz, but there you go. All it really needs to do is send information once an hour.
Hopefully I will get more info at some point, I was just looking for a way to do it without using another cable. I asked about wireless (my first option) but apparently no chance.