H-552 552dectapeCtlr Apr66

This document is an instruction manual for the Type 552 DECtape Control, published by Digital Equipment Corporation in 1966.

Its primary purpose is to provide comprehensive information for maintenance personnel, covering functional descriptions, control logic, circuit details, and maintenance procedures.

The DECtape Control 552 facilitates binary data transfer between PDP-5 or PDP-8 digital computers and up to eight DECtape transport drives (Type 555 or TU55). Key operational features include the transfer of 12-bit computer words, block addressing via mark and timing channels, and various control modes for reading, writing, and searching tape. It utilizes the computer's high-speed data-break facility and flags (DECtape Flag and Data Flag) to manage data transfers and signal program interrupts, allowing concurrent computation during tape operations.

The manual details the DECtape format, instructions, and functional elements like data buffers, registers, and error flags. It delves into intricate control logic and circuit descriptions, including conventional and specialized components, complemented by engineering drawings. Furthermore, it outlines preventive maintenance schedules (daily, weekly, periodic) and corrective maintenance procedures, emphasizing the use of specific test equipment and detailed wiring/module information for troubleshooting.