Hi Charles,
In addition to Sergey's advice, I can add all of the drawers I've worked with only need a pulse to open. I haven't seen one that notifys the program when it's closed. The open pulse triggers a relay which opens a mechanical latch. Issuing another open pulse does no harm when the draw is already open.

>Hi All!
>
>I have this project regarding a POS system and like all POS systems, it uses a cash drawer. I know already how to programmatically open the cash drawer, but my dilemna now is how do i determine if it has already been closed. I was able to open the drawer by opening a communication port (COM1) using FOPEN and "wrote" some character data to open it using FWRITE. Question is, how do i know if the cash drawer was closed already? When the cash drawer closes, does it "write" back something? If so, what?
>
>Thanks in advance.