Step 1: Understand POS systems.
POS (Point of Sale) systems are used in retail stores to handle billing, payments, and transactions.
Step 2: Identify hardware components.
A POS system typically includes devices like a computer, barcode scanner, receipt printer, and cash drawer.
Step 3: Analyze the statement.
The sentence refers to how many cash drawers are usually connected to a retail POS system.
Step 4: Determine the correct word.
Generally, a POS system is connected to one cash drawer for handling transactions.
Step 5: Final answer.
Thus, the blank is filled with one.