DECcommEquipment aug67

This 1968 document from Digital Equipment Corporation (DEC) serves as a comprehensive manual for their data communication equipment, designed primarily for PDP computers. It provides detailed information on product lines, application examples, technical specifications, and interfacing characteristics.

The document highlights DEC's modular design approach for building flexible and cost-effective communication systems for various industrial, scientific, military, and commercial applications, from a few remote terminals to multi-station message switching networks.

Key equipment and capabilities covered include:

1. Low-Speed Serial Asynchronous Communications (0-300 baud):

   • PT08 Serial Line Interface: A hardware-intensive solution for 1-5 full-duplex channels, primarily for Teletype (20mA dc keying) or EIA RS-232B (modem) connections. Character assembly is handled by dedicated hardware.
   • 680 Data Communication System: A computer-based system (using a PDP-8) designed for up to 128 asynchronous lines (0-150 baud). It leverages software for bit-by-bit character assembly and control, making it more economical and flexible for multi-channel applications. It supports local Teletype, telegraph lines, and asynchronous modems, with options for automatic answering and dialing.

2. Medium to High-Speed Communications (1200-200,000 baud):

   • DP01A Synchronous Modem Interface: Provides a single full-duplex synchronous channel (up to 50K baud) for high-speed data transfer, interfacing with synchronous modems via EIA RS-232B. It supports program-supervised data transfer and optional automatic calling units.
   • Type 636 Asynchronous Data Communication Channel: A special-order single-channel, full-duplex asynchronous interface (up to 250K baud) that provides program-supervised control of associated modems, including automatic answering and optional automatic dialing.

3. Automatic Dialing Equipment:

   • DP02A/DP03 Automatic Dialing Equipment: Enables a PDP computer to control up to four Bell Model 801 Automatic Calling Units (ACU) for program-controlled dialing on telephone networks, typically associated with PT08 or DP01A channels.

4. Parallel Data Channels:

   • DM03 Data Channel: An example of a high-speed parallel interprocessor interface for rapid, bidirectional data transfer between a 12-bit PDP computer and external 36-bit digital devices, often operating memory-to-memory.

The document also details how these components are configured and programmed, and provides specific module schematics and operational characteristics for various interfaces (e.g., Teletype, EIA RS-232B modems, telegraph lines). Example applications include airline reservation systems, time-sharing services, multi-terminal data processing, and process control networks.