I have a question, why is rs485 limited to less than 100 meters at 10mpbs ( mbaud ) and is 100Base-TX ethernet applicable on 100 meters with 100 mbps bitrate
i know that rs485 normally use a sort of NRZ encoding with 2 levels and ethernet uses a MLT-3 4B5B encoding with 3 levels
but i cannot understand why the difference between distance and baudrate of ethernet and rs485 is more than a factor 10 (ethernet has an actual baudrate of 125mbps due to 4b5b encoding)
and theoretical if 100base-tx would run at half speed would the usable distance then muliply with 2?
endgame for me would be to create an 2 wire (half-duplex) master slave (rs485-like )network with around 200 nodes , a length of 1000 meters and a speed of ~10 mbps.
or alternatively a half duplex P2P network like EtherCat but simpler like rs485 but with a usable distance of 200 meters and a speed of ~10mbps
-source of rs485 distance baudrate graph https://www.maximintegrated.com/en/images/appnotes/3884/3884Fig06.gif