DECscope

This "DECscope User's Manual" provides comprehensive information for the DECscope (VT50) family of video terminals, specifically the VT50, VT50H, and VT52 models, highlighting their display capabilities (12-line uppercase or 24-line upper-and-lower-case).

The manual is structured for different users:

1. For Owners: It covers preparing the environment, installing the DECscope, connecting it to a computer (including setting Baud rates), addressing screen irregularities, and options for user and Digital Equipment Corporation maintenance.
2. For Operators: It offers a series of practical experiments to familiarize users with the terminal's basic functions in off-line mode, such as power-on, cursor movement, typing, scrolling, and the use of various keys (e.g., RETURN, TAB, SHIFT, CAPS LOCK, SCROLL, BREAK).
3. For Programmers: This section details the DECscope's functionality as both an input and output device, explaining how it processes and transmits characters using ASCII codes and serial encoding (bits, parity, stop bits). It describes the terminal's internal microprocessor and memory. Key technical topics include:
   • Detailed explanations of keyboard keys and their corresponding transmitted codes, noting differences in case handling and special functions across models (VT50/VT50H vs. VT52).
   • Commands the terminal responds to, including displayable characters, control codes (like ESC sequences for special functions), cursor movement (basic and advanced), and screen erasure commands.
   • Synchronization mechanisms using XOFF/XON signals and an internal buffer ("Silo") to manage data flow, especially when the terminal's copier is in use or in "Hold-Screen Mode."
   • Advanced features like "Alternate-Keypad Mode" and "Graphics Mode" (VT52 only), which allow for unique input and special symbol displays.
   • Information on audible signals (key click, bell) and how software can identify the terminal model.

Appendices provide specific Baud rate switch settings and a display of special graphic symbols available on the VT52. The document concludes with a summary of the terminal's physical and electrical specifications.