DM74LS156 Datasheet
Dual 2-Line to 4-Line Decoders/Demultiplexers
Manufacturer: Fairchild (now onsemi)
Download the DM74LS156 datasheet PDF.
This datasheet also includes the DM74LS155 variant, as both parts are published together in a single manufacturer document.
Note: The manufacturer provides a single datasheet file (DM74LS155_FairchildSemiconductor.pdf) that lists specifications for multiple related part numbers.