MP00056 RH20 Apr81

This document is a "Field Maintenance Print Set" (order number MP00056) for the Digital Equipment Corporation RH20 MASSBUS Interface.

It provides comprehensive technical documentation for the RH20 system, covering its design, configuration, and maintenance. The print set includes:

1. Module Documentation (Schematics, Layouts, Parts Lists): Detailed circuit diagrams, physical board layouts, and component lists for the core interface modules:

   • M8555: MASSBUS Control EBUS (External Bus) Interface.
   • M8556: MASSBUS Control CBUS (Console Bus) Interface.
   • M8557: MASSBUS Control MBUS (MASSBUS) Interface.
   • Separate documentation for Power, Ground, and Capacitors for each module type.

2. System-Level Information:

   • Table of Contents: Outlines all included documents.
   • Module Utilization: Diagrams showing how modules are used within the RH20-DTE20 system.
   • Cabling: Specifications for EBUS and CBUS cables (e.g., EBUS Cable I/O to CPU) and MASSBUS cables.
   • Terminator Pack Assembly: Details for the MASSBUS terminator.
   • Instruction Format: Documentation defining the control registers (e.g., CONO, CONI, DATAO, DATAI, SBAR, STCR, PBAR, PTCR, IVIR, RR, WR, DCR) and their bit assignments for the RH20.
   • RH20 Block Diagram: A high-level overview illustrating the interconnections and data flow between the EBUS, CBUS, MBUS, and various control components.
   • Acceptance Procedure: Instructions for testing, adjustments (like clock deskew), margins, and error rates for the RH20.
   • Accessory Ship List: A list of accessories for the RH20 controller.
   • MASSBUS Transition: Documentation related to the MASSBUS interface.

The primary purpose of this document is to serve as a complete technical reference for field service personnel to understand, install, troubleshoot, and maintain the RH20 MASSBUS Interface.