The Sharp ER-A520 cash register is of course no longer made. If you are still using one you could add PC Poll to it if you really wanted to. Adding PC Poll would be a great idea if you are bar code scanning so you can back up and save your UPC database.
PC Poll will allow you to back up your UPC database and transfer it to one of the new SAM4s cash register systems for bar code scanning before your Sharp ER-A520 stops working which could be anytime now. Stop tempting fate and upgrade now, call us at 800-863-2274 to discuss your options.