DUP11 Bit Synchronous Interface

This document covers the maintenance of the DUP11 Bit Synchronous Interface, which provides a data path between a synchronous modem and the PDP-11 Unibus. The manual is organized into five chapters:

• Introduction: General description of the DUP11 and SDLC/DDCMP protocols.
• Installation: Procedures for module installation, device and vector address selection, and cabling.
• Register Descriptions: Detailed bit assignments for control, status, and data buffers.
• Theory of Operation: Functional and detailed logic descriptions, including CRC logic and interrupt handling.
• Maintenance: Preventive and corrective maintenance philosophies, diagnostic programs, and test equipment requirements.

Also includes three appendices regarding memory organization, logic symbology, and integrated circuit descriptions.