DEC-10-HDSA-D DS10 Single Synchronous Line Unit Dec70

This document is the Digital Equipment Corporation PDP-10 Maintenance Manual for the DS10 Single Synchronous Line Unit, published in December 1970 (DEC-10-HDSA-D).

The DS10 is an interface unit designed to connect a PDP-10 I/O Bus to a serial-synchronous modem communication link, compliant with EIA Standard RS-232-B (or C). Its primary function is to facilitate data exchange by converting parallel 36-bit words from the PDP-10 into serial bit streams for transmission, and converting serial data from the modem back into parallel words for the PDP-10. It supports both full-duplex and half-duplex operations, with character lengths of 6 or 8 bits (programmable) and speeds up to 20,000 bps. The unit is compatible with various Bell System data sets and can manage modem control signals. Multiple DS10 units can be installed with a single PDP-10.

The manual provides comprehensive information across six chapters:

1. Introduction: Covers the purpose, a general and functional description of the DS10, its data format (including sync characters and character lengths), and detailed specifications (speed, interface, power, physical dimensions).
2. Installation and Interface: Details the physical mounting of the DS10 in a standard DEC cabinet, cabling requirements for connection to the PDP-10 I/O Bus, modems, and indicator panels, and a thorough explanation of the various EIA Standard RS-232-C interface circuits used for data and control signals.
3. Operation and Programming: Describes the DS10's indicator panel for status monitoring and outlines the PDP-10 I/O instructions (CONO, CONI, DATAO, DATAI) used to control and program the unit, including bit assignments for status and data registers, and how high and low priority interrupts are generated.
4. Principles of Operation: Explains the internal logic of the DS10, encompassing control logic (device selection, instruction decoding, status conditions, priority interrupts), receive logic (buffer, shift register, character counter, sync and End-of-Transmission detectors), and transmit logic (data buffer, shift register, sync character detector, last bit detector, character counter). It details the complete receive and transmit sequences of operation, including an "Idle Mode" for maintaining modem connections and a "Diagnostic Mode" for testing.
5. Maintenance: Provides procedures for preventive maintenance (mechanical checks, power supply verification, and delay adjustments) and troubleshooting. It also describes the use of specific diagnostic programs (MAINDEC-10-D2KB, D2LA) to test the DS10's functionality.
6. Engineering Drawings: Includes a list and a complete set of engineering drawings for reference during maintenance.

A prior understanding of the PDP-10 Central Processor and communication modems is noted as essential for fully comprehending the manual.