American Express cards have a four-digit code printed on the front side of the card above the number.

The elevator door opened; both men walked in, and the armed attorney pressed the four-digit code for the floor as it had been given.

After an instant's hesitation, he tapped out a four-digit code.

To start the car, the driver punches in a four-digit code.

At his apartment door, he removed a small keypad and punched in the four-digit code.

Each entry is given a four-digit code according to the type of overtime claimed.

At the far end, he punched the new day's four-digit code on a keypad, and the door popped open.

And, you know, it's very breezy to type in a four-digit code.

You have a four-digit code to open and close your door.

Sylvia punched in her four-digit personal code, and the door opened inward.