A couple possible suggestions...
1) After pressing the F12 Tender button, highlight the tender that is to be used, and press the + symbol on the numlock keypad. This will auto fill in the remaining balancing and it does press enter for you.
2) you could install a programmable keyboard onto the register system. These keyboards allow you to program buttons on the keyboard to do specific tasks for you. for example, you could program a keyboard to do the following..
On the press of the keyboard button labeled 'Visa', it would do the following..
- Press F12 Tender button
- down arrow, down arrow, down arrow (basically however many down arrows it takes to get to the Visa tender.
- + (numlock + symbol so it auto fills in the amount due, and presses enter.)
now the credit card number screen should be visible, waiting for the cashier to swipe the card.
all of that was completed just by pressing one single button on the keyboard. I do have experiencing in programming these keyboards. Ask if you have any questions.