Serial output circuit into arduino

Hi there might be an obvious answer to this question but i need to find a way to use the data output from this circuit into the serial input of my arduino.

http://www.csc.liv.ac.uk/~greg/projects/rdmeter_hw.pdf
Does anybody have any ideas??

Is it just a case of 5volts down the rts and dtr lines, grnd to grnd and rx/tx to the rx on the arduino. Or is it not that simple.

This is an irda reciever that plugs into a pc serial port to recieve data but i would like my arduino to recieve this data instead.

Many Thanks

RTS and DTR on the right hand side are outputs From something else, and Rx/Tx are outputs To something else?