VT510
| Company type | Public |
|---|---|
| Industry | Computer hardware |
| Founded | November 8, 1957 in Maynard, Massachusetts, United States |
| Fate | Terminal division discontinued in August 1995 |
| Headquarters | Maynard , United States |
| Products | VT520 computer terminal, VT500 series terminals |
The VT520 represents an ANSI-compliant computer terminal launched by Digital Equipment Corporation (DEC) during 1993–1994. This model is a monochrome, text-only terminal capable of handling multiple sessions simultaneously and features an integrated 14-inch display. In comparison, the VT510 was designed for single-session use, whereas the VT525 introduced color capabilities and utilized an external monitor setup.
The VT500 series succeeded DEC's prior VT lineup, which included the VT420 (text terminal) and the VT340 (graphics terminal). Released in response to growing competition from affordable IBM PC clones running terminal emulators, the VT500 family offered a streamlined, budget-friendly alternative. DEC discontinued its terminal division in August 1995 after selling roughly six million units, marking the end of the VT series.
Post-DEC, the VT520 continued to be available through Boundless Technologies until that company closed in 2003.
Description
During the mid-1990s, as PC prices dropped below $1000 and terminal emulators gained popularity, dedicated terminals faced significant challenges. DEC’s VT500 series was developed as a cost-efficient and simplified replacement for the VT420 and VT340 models. These text-only terminals incorporated an RS-232C serial interface, a Centronics port, and a PS/2 keyboard connector to facilitate integration in diverse environments. Additionally, they maintained two proprietary DEC MMJ serial ports alongside dedicated keyboard connections.
Introduced in 1993, the VT510 combined all components into a single unit with a built-in 14-inch screen. The VT520 shared this design but expanded functionality by supporting up to four sessions simultaneously via TD/SMP (referred to as SSU on terminals). The subsequent VT525 model enhanced this lineup by adding color support and adopting a slim pizza-box chassis featuring an SVGA output for external monitors.
All models within the VT500 range primarily functioned as ANSI-standard terminals. While the VT510 supported only one session, both the VT520 and VT525 could handle up to four sessions—doubling previous session capacities. Users could toggle between active sessions using keyboard shortcuts or view multiple sessions concurrently through horizontal or vertical screen splits. The terminals came equipped with multiple ROM-based character sets, covering DEC standard, international alphabets, and PC-compatible characters. They also allowed customization through sixel graphics and single-character substitutions via the National Replacement Character Set to accommodate various regional keyboard layouts.
Serial communication speeds were improved to 115.2 kbps compared to earlier models’ 38.4 kbps. Each serial port was capable of managing two sessions over TD/SMP connections. Emulation support extended across legacy models such as the VT100 and VT52, along with other popular terminals like Wyse, ADDS, and TeleVideo. Besides ANSI color command compatibility, these devices also recognized previous proprietary escape sequences.
A significant enhancement included embedded desk accessory applications running on the terminal’s CPU, such as a calculator, alarm clock, calendar utility, and character set viewer.
In many Terminal emulator specifications, references to the VT500 series collectively denote compatibility with all three models: VT510, VT520, and VT525.