Ri id mifare write problem

I bought a new RF ID Mifare device from nsk.i want tto write a encryption key to the rf id tag.how is it possible?how do i write a code into it?http://www.nskelectronics.com/mifare_rfid_rw_.htmlthis is my product

HI, I am working on Performance analysis of hybrid optical OFDM on optisystem.
I have problem after coherent detection. There is no signal after OFDM Demodulator.
CONSETLLATION GRAPH IS NOT SHOWING ANYTHING.
The Trasmitter side is working properly.

Manpreet,have you done this rf id writing?