DECtape Control 551

This manual provides a detailed description of the DECtape Control Type 551, a component used in PDP-6 systems to manage data transfers between magnetic tape transports and the arithmetic processor. It covers:

• System Description: The relationship between the Data Control Type 136, the 551 Control, and Type 555 Transports, including data formats and register functions.
• Theory of Operation: An analysis of initialization, timing pulse generation, command decoding, and error-checking mechanisms.
• Maintenance: Preventive and corrective maintenance procedures, including module testing, marginal checks, and a comprehensive list of recommended spare parts.