The SN74LS257BN is a 2-to-1 quadruple Data Selector/Multiplexer with 3-state outputs. It is designed to multiplex signals from four-bit data sources to four-output data lines in bus-organized systems. The 3-state outputs will not load the data lines when the output control pin (G\\) is at a high-logic level.
Three-state outputs interface directly with system bus
Provides bus interface from multiple sources in high-performance systems
