DECtape Control Type 550

This document provides a comprehensive technical overview of the Type 550 DECtape Control unit. It details the system's ability to provide magnetic tape storage with the convenience of paper tape, specifically designed for use with PDP-1, -4, and -7 computers. The manual covers functional operation, including data transfer, word counting, and mark track decoding. It further describes the three programmed modes of operation (search, read, and write), error response handling, and provides detailed specifications and programming instructions. The document concludes with sections on system maintenance, corrective troubleshooting procedures, and interface details for connecting to computer systems.