Trying to connect Rs232 of SDc12XX using beaglebone

I modified the Roboteqdevice.cpp cflags to 115200, 8N1 as mentioned in the datasheet but I get the error
Opening port: '/dev/ttyO4'...succeeded.
Initializing port......done.
Detecting device version...failed (issue ?$1E response: 4).
Error connecting to device: 7.

I was able to work fine with the USB port (but as it is suggested to use RS232 and also its vary fragile so I want to use RS232)
Can someone direct to the correct .cpp file or suggest what I might have done wrong

Hello jaghvi,

Let's make sure first that the serial port works correctly.

Connect Rx and Tx (pin 2 and 3 on DB9 connector of the USB to Serial adapter). Then open terminal program (like "minicom") and using that serial port type few chars on the keyboard. You should see what you are typing on the terminal.

Please, make sure that what you are typing is exactly what you see on the terminal. If you see garbage on the terminal - check serial port baud rate and parity settings.

If the problem was neither in the serial-USB adapter nor in serial port, get back to forum - will investigate further

Regards