One tablet at the counter, the office on any screen. VAT worked out per line and frozen there, receipts that stand as simplified invoices, and a day that ends with the drawer counted.
The counter keeps working through a dead line: the sale is queued on the tablet, the PIN is checked there, and everything syncs when the connection comes back. Nobody is turned away and nothing is written on paper.
A fiscal number that runs unbroken, carrying the shop and the tablet it came from. A refund is a new record pointing at the old one — nothing is edited and nothing is deleted, which is the promise made to whoever audits it.
Expected cash against what is actually in the drawer, with the float and anything paid out of it. The difference is written down rather than absorbed, so a drawer that is short says so on the day it happened.
A barbershop pays a percentage and asks for a PIN per sale. A café does neither. Both are settings a business is born with or changes later, and turning one off deletes nothing — the rules stay where they were left.