The 74F403A is an expandable fall-through type highspeed First-In First-Out (FIFO) Buffer Memory optimized for high-speed disk or tape controllers and communication buffer applications. It is organized as 16-words by 4-bits and may be expanded to any number of words or any number of bits in multiples of four. Data may be entered or extracted asynchronously in serial or parallel, allowing economical implementation of buffer memories.