This part is a kind of semiconductor called STL-S3E.
Function of this product has Stratum 3E Timing Module.
Manufacturers : Connor-Winfield
Image and pinout :

Some of the text within the PDF file :
Stratum 3E Timing Module STL-S3E 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 • 12 ppb Composite Hold Over Mode • Fast Acquisition Mode • Manual/ Autonomous Operation • Master/Slave Configuration • Revertive/Nonrevertive Modes Application The Connor-Winfield Stratum 3E Simplified Control Timing Module acts as a complete system clock module for Stratum 3E 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 3E Timing module helps reduce the cost of your design by minimizing your development time and maximizing your control of th [ ... ]
STL-S3E PDF Datasheet Download
