Arduino working as a keyboard

Hi
next question. Since the software which is running in the background frequently asks for the device state and getting a device state over the usb takes very long i would like to use the RS232 Port (found a shield http://www.cutedigi.com/arduino-shields/rs232-shield-for-arduino.html)for the keyboard emulation. Is this possible or do I have to change anything ?

Thanks in advance

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