The one time I messed with this, the cash drawer was interfaced with the PC via a RS232 serial port. You would open the cash drawer by sending a specific character sequence directly to the port. You could also check the status of the drawer, to see if it was open or closed.
There are pretty sophisticated add-on libraries for this, which also take care of the POS scanner.
>Hi to all,
>
> How do I print in a POS printer and eject the cash register?
>
>Thanks in advance
-- Larry Keyes
Remember only You can prevent Gray Goo. Never release nanobot assembers without replication limiting code.