These data selectors/multiplexers are designed to multiplex signals from 4-bit data sources to 4-output data lines in bus-organized systems. The 3-state outputs do not load the data lines when the output-enable () input is at a high logic level. The SN54ALS257A and SN54ALS258A are characterized for operation over the full military temperature range of -55°C to 125°C. The SN74ALS257A, SN74ALS258A, SN74AS257, and SN74AS258 are characterized for operation from 0°C to 70°C.