DZ11 User's Manual

This document is the DZ11 User's Manual, a "Revised Preliminary Edition" published in June 1977 by Digital Equipment Corporation (DEC).

The manual describes the DZ11, an asynchronous multiplexer designed to interface a PDP-11 processor with eight (or sixteen, using two modules) asynchronous serial communication lines.

Key aspects summarized include:

• Functionality: The DZ11 is used for applications like communications processing, time-sharing, transaction processing, and real-time processing. It supports speeds up to 9600 baud and offers flexible control over communication parameters such as baud rate, character length, stop bits, parity, and interrupt handling for each line. It also provides limited data set control (for EIA models), break generation/detection, and silo buffering for received data.
• Configurations: The DZ11 is available in several configurations, supporting either EIA RS232C interfaces (with partial modem control) or 20 mA current loop signaling (for local terminals without modem control).
• Physical Components: It typically consists of one or two hex SPC modules (M7819 for EIA, M7814 for 20 mA) and an unpowered distribution panel (H317-E for EIA, H317-F for 20 mA), connected by ribbon cables.
• Specifications: Detailed electrical, environmental, and performance specifications are provided, including power requirements, operating temperature, humidity, cooling, signal distortion, and supported baud rates. It notes that reliable communication distances vary based on cable type and environment, particularly beyond 50 feet for EIA and depending on noise for 20mA.
• Installation: Procedures for unpacking, inspecting, and installing the modules and distribution panels are outlined, including setting address and vector switches. It specifies which external cables (for connecting to modems or terminals) are not supplied with the DZ11.
• Programming: This section describes the various device registers (Control and Status, Receiver Buffer, Line Parameter, Transmit Control, Modem Status, Transmit Data), their bit assignments, and programming constraints. It explains how to control the device's features, including managing receiver and transmitter interrupts, emptying the received data silo, transmitting characters, and using data set control (for EIA versions). Sample programming examples are included.

In essence, the manual serves as a comprehensive guide for understanding, installing, and programming the DEC DZ11 asynchronous multiplexer for PDP-11 systems in the late 1970s.