Unable to set serial mode - Inappropriate ioctl for device (25)

[kaktoos]

Hi,

I have trouble with reading values at Moxa uc5100 series using this plugin.

When I try:
./check_modbus --serial=/dev/ttyM3 --serial_bps=115200 --serial_mode=1 -d 1 -a 3200 -f 4 -n

I have ioctl error message:
check_modbus.c:321:set_serial_mode(): Unable to set serial mode - Inappropriate ioctl for device (25)
check_modbus.c:140:print_error(): Unsupported return code (3)

could you please take moment to look what could cause this issue?

Thanks!