DECdataway user's guide

This user's guide provides comprehensive information for the installation and maintenance of the Digital Equipment Corporation (DIGITAL) DECdataway subsystem. The DECdataway facilitates block or message-oriented data transfer between a PDP-11 computer and up to 63 slave peripherals (ports) using an ISB11-A controller and a multidrop cable.

The subsystem's physical description includes the ISB11-A controller (comprising a KMC11-A microprocessor and M8202YE Line Unit module) and its connection via a shielded, twisted-pair cable (Belden 9182 recommended, with a maximum length of 4572 meters). Communication is governed by DSBC (DEC Serial Bus Control) protocol, ensuring error-free message transfers between the master controller and slave ports through a round-robin polling scheme.

Installation procedures emphasize thorough site preparation, including accessibility, space, environmental considerations (temperature, moisture, static electricity), and proper electrical grounding. Detailed instructions are provided for cable routing, stressing the importance of minimizing electrical and electromagnetic interference by maintaining distance from various power sources and lighting. The guide also covers the specific steps for connecting the DECdataway cable to both controller and port connectors, including setting address jumpers for port selection, and installing the ISB11-A controller hardware and software (diagnostics).

For user's maintenance, the document outlines preventive measures such as periodic cable inspection, monitoring signal amplitudes, and performing resistance checks. It also lists a series of standalone and system-level diagnostic tests (e.g., MAINDEC-11-DZKCC, MAINDEC-11-DZKCH) to identify and troubleshoot issues related to the controller, cable, or terminals, thereby ensuring system reliability and performance.