VT103
| Industry | Computer hardware |
|---|---|
| Founded | November 7, 1957 |
| Fate | Acquired by Compaq (1998) |
| Headquarters | Maynard, Massachusetts , United States |
| Products | Computers, computer terminals (including VT100) |
The VT100 is a video terminal launched by Digital Equipment Corporation (DEC) in August 1978. It was one of the earliest terminals to implement ANSI escape codes for cursor manipulation and additional operations, introducing extended codes for features such as keyboard indicator lights. This innovation significantly contributed to the widespread acceptance of the ANSI standard, which later became the de facto standard for both physical terminals and terminal emulator software.
The VT100 family, especially the VT102 model, commanded a dominant position in the market and secured DEC’s status as the foremost terminal manufacturer. The series was succeeded by the VT200 series in 1983, which continued its legacy of success. Collectively, the VT line achieved sales exceeding six million units, largely propelled by the VT100’s strong market presence.
Description
DEC’s early video terminals began with the VT05 in 1970, followed by the VT50 in 1974 and the VT52 in 1975. The VT52 offered an 80×24 character display with bidirectional scrolling and programmable cursor control, delivering "smart terminal" functionality over affordable serial connections—unlike proprietary solutions such as the IBM 3270, which depended on costly controllers. More basic "dumb terminals" like the ADM-3 (1975) lacked full cursor positioning capabilities and competed primarily on price.
Released in August 1978 as a successor to the VT50/52 series, the VT100 communicated via serial interfaces supporting speeds from 50 bit/s up to 19,200 bit/s—doubling the maximum rate of its predecessor.[1] It featured an optional "smooth scrolling" mode that shifted text incrementally to enhance readability, albeit at some expense to throughput.
A major advancement was its adoption of the emerging ANSI X3.64 control code standard instead of proprietary command sets. Although initially doubted due to perceived complexity and cost, improvements in affordable microprocessor technology and memory allowed DEC to implement this standard using an Intel 8080 CPU.Cite error: The opening <ref> tag is malformed or has a bad name The VT100 also retained backward compatibility with older VT52 control sequences.[2]
Other enhancements comprised a 132-column display mode and various graphic attributes such as blinking text, boldface, reverse video, underlining, and double-sized or double-width characters. It introduced a specialized box-drawing character set designed for creating on-screen forms.
Configuration was handled through interactive on-screen menus with preferences saved in built-in non-volatile memory. Its modular construction facilitated maintenance by enabling swift component replacement.
Internally, the terminal’s functions were split between two circuit boards: a video monitor board responsible for CRT adjustments like electron beam alignment,Cite error: The opening <ref> tag is malformed or has a bad name and a terminal controller board containing logic components including DEC’s Intel 8080 processor.
In 1983, DEC succeeded the VT100 with more sophisticated terminals from the VT200 series, including models such as the VT220.
Options
The VT100 supports a variety of expansion boards from both DEC and third parties, notably Digital’s own VT1XX-AB (Advanced Video Option) and VT1XX-AA (20 mA Current Loop Option). These expansions enhance terminal functionality as described in the VT100 User Guide.
Variants
The VT100 marked Digital’s first terminal built around the industry-standard Intel 8080 microprocessor. Expansion possibilities included external printer interfaces, enhanced graphics capabilities, and increased character memory. The "Advanced Video Option" (AVO) allowed display of 24 lines in 132-column mode compared to only 14 lines on the base unit. This architecture served as a foundation for several related hardware products.
Lower-cost models without expandability followed, including the VT101 (a basic VT100 variant) and VT102, which incorporated AVO and a serial printer port as standard features. The VT105 introduced rudimentary graphics through waveform graphics, enabling simple charting by overlaying graphical elements onto text screens. The VT125 improved graphic support using the efficient Remote Graphic Instruction Set (ReGIS), transmitting specialized ANSI commands rather than switching modes.
The VT131 added block mode capability for local form entry, enhancing interactivity by submitting completed forms back to host systems.
DEC utilized the ample physical size of the VT100 chassis to integrate minicomputer systems. The VT103 incorporated an 8-slot Q-Bus backplane housing a 16-bit LSI-11 microcomputer, optionally paired with dual TU58 DECtape II cartridge drives serving as slow disk storage alternatives. The VT180 ("Robin") contained a Zilog Z80 single-board computer running CP/M. The VT278 (DECmate) featured a PDP-8 processor designed to operate Digital’s WPS-8 word processing software.
See also
References
- Notes
External links
- History of DEC video terminals Archived version
- VT100 User Guide
- Technical Manual for VT100 Series
- ECMA-48 Standard
- The DEC section on Terminals Wiki