Yeah its possible and very convenient. You don't need XModem for this. XModem is useful when you are planning to send some pdf or any other format file.
In your C program, just create a serial socket connection on port on which module is connected. Then simply push/write data on one side and pull/receive it on other end. I have written a python script for this, you can use it for reference:
ser = serial.Serial('COM7', 9600, timeout=2)
print "Connected to COM17"
ser.write("Tx data here")