Hi Vishal
Make connections in the following manner: Short both these pins, anode of RX (emmiter) and cathode of TX, and then connect them to the GND pin of microcontroller. Also give +5 V to TX's anode using a current limiting resistor(1K would be fine) in series. Pull-up the RX's cathode (collector) using a 10K. This cathode-10K junction would now give you the analog voltage that you'll need to work with. This is so because the RX part behaves like a 3 pin NPN transistor with its emmiter and collector pins as told above while the base pin is the IR light it receives from the TX part.
Hope this helps
Good luck 