>I have can do financial transactions over the internet (e-banking).
>I surf to the bank' home-page and if I want to do a transaction the page checks my identification. There's a serial device connected to my computer that gives the bank my ID.
>
>Do you know how this is done? How can they (over the internet) send and recieve data from that device??

Being Web-challenged, I'm afraid I can't help you in this regard.