Several devices on one simulated line, as devices share an RS485 pair: every frame reaches
all of them, the one it is addressed to answers, and each carries out a broadcast write.
The line shares each device, so the program's ModbusServer still reads and changes it.
A serial port with the line on its far end: every frame written reaches each device,
and whatever they answer waits to be read. Devices put on the line later are on the
port too.
Several devices on one simulated line, as devices share an RS485 pair: every frame reaches all of them, the one it is addressed to answers, and each carries out a broadcast write. The line shares each device, so the program's
ModbusServerstill reads and changes it.