I use Duali NFC pad and I want to write a C# program for communicate with it. NFC pad has a program that communicates with this though the driver.
I want know about this driver and its DLL files if it exists.
Indeed, this driver is for Duali products. I have checked their official website and it appears there is a common driver available for all their products which implies that this is the one on their website as well. You need to visit the page listed below in order to install the NFC pad.
Download page: http://duali.com/eng/support/nfc-reader-driver.html