You have accidentally re-programmed the CASH (TL) button while trying to program something else.
Try this:
Turn key to PGM mode
008
X (next to decimal point)
#/TM/ST (SUBTOTAL button)
TL/NS (CASH button)
Note: on some versions, #/TM/ST is called SUBTOTAL and TL/NS is called CASH
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If anyone needs more information, the Sharp XE-A203 manuals are here:
http://the-checkout-tech.com/manuals/cashregisters/Sharp12.php
Registerman, November 2011