This part is a kind of semiconductor called LS1240.

Function of this product has Octal 3-STATE Bus Driver.

Manufacturers : Fairchild Semiconductor

Image and pinout :

Some of the text within the PDF file :

DM74ALS1240A Octal 3-STATE Bus Driver September 1986 Revised February 2000 DM74ALS1240A Octal 3-STATE Bus Driver General Description These octal 3-STATE bus drivers are designed to provide the designer with flexibility in implementing a bus interface with memory, microprocessor, or communication systems, and are low power dissipation versions of the DM74ALS240A and DM74ALS241A. The output 3-STATE gating control is organized into two separate groups of four buffers. The DM74ALS1240A control inputs symmetrically enable the respective outputs when set logic LOW. The 3STATE circuitry contains a feature that maintains the buffer outputs in 3-STATE (high impedance state) during power supply ramp-up or ramp-down. This eliminates bus glitching problems that arise during power-up and power-down. [ ... ]

LS1240 PDF Datasheet Download