Without actually having a clue, I suspect this would depend on the software controlling the smartcard reader, and the OS.
What you are looking for is that the smartcard reader detects a card and sends an event to the OS, witch in turn handles it.
I suggest you try to get hold of a technical manual for the reader, and find out if it sends a signal, and if so what signal it sends to the OS.
Then I also suggests that you brush up on API calls in the OS, so that you can catch the signal when it comes (Specifically events regarding the COM, Paralell, or whatever port you have connected the reader to).
If you are lucky, there may be some (debug) software designed to keep listening to the different HW ports, and display when and what signal calls that arrives. I don't know of any, but you may have better luck in the c or c++ forum.
This is a whole lot of nothing I know, but maby it will point you in the correct direction...
Good Luck!
-Mats Hulten