This part is a kind of semiconductor called STL-S3.

Function of this product has Stratum 3 Timing Module.

Manufacturers : Connor-Winfield

Image and pinout :

Some of the text within the PDF file :

Stratum 3 Timing Module STL-S3 2111 Comprehensive Drive Aurora, Illinois 60505 Phone: 630- 851- 4722 Fax: 630- 851- 5040 www.conwin.com Features • 6 Input References • Hitless Switch Over • CMOS output up to 77.76 MHz • 8 kHz Output • Fast Acquisition Mode • Manual/ Autonomous Operation • Master/Slave Configuration • Revertive/Nonrevertive Modes Application The Connor-Winfield Stratum 3 Simplified Control Timing Module acts as a complete system clock module for Stratum 3 timing applications in accordance with GR-1244CORE, Issue 2, GR-253-CORE, Issue 3, and ITU-T G.812, Option ΙΙΙ. Connor-Winfield’s Stratum 3 Timing module helps reduce the cost of your design by minimizing your development time and maximizing your control of the system clock with our simplified design [ ... ]

STL-S3 PDF Datasheet Download