These devices contain four independent 2-input positive-NAND buffers with open-collector outputs. They perform the Boolean functions Y = A B or Y = A + B in positive logic. The open-collector outputs require pullup resistors to perform correctly. These outputs may be connected to other open-collector outputs to implement active-low wired-OR or active-high wired-AND functions. Open-collector devices often are used to generate higher VOH levels.