Modbus RTU serial port

• In order to use a serial port, (pwrp) user must be a part of dialout group
• The port device has to be set to 0777 permission

• The port device (name) may be /dev/ttyS0 (for a pci card) or /dev/ttyMI0 (Moxa card) or /dev/ttyUSB0 (usb/serial converter)

Examples of useful commands:

chmod 0777 /dev/ttyS0

chmod a+rw /dev/usb/002/003

ls -l /dev/ttyS0

lsusb

dmesg | grep tty