I need to multiplex one single uart port over three different (separated) rs-485 systems.
I can only work on master side, slaves/cabling are already in place and cannot be modified.
- single rs-485 master (microcontroller with only one uart port)
- each rs-485 sub-system built with about 700mt shielded twiestd pair cable with multiple rs-485 slaves (that may or may not have isolated interface)
- a slave can only send data when master ask it to do
- 19200bps or slower speed, half-duplex
What do you think about following solution?