Home Page
        Orders     Downloads     Support     Contact     Deutsch

VT100 Terminal Emulator

ZOC Terminal is a powerful terminal emulator offering an industrial strength implementation of the VT100 emulation, which lets you access a variety of servers via telnet or secure shell (SSL/SSH) connections.

VT100 related features:

  • Very good (near perfect) vttest score of 105
  • ASCII and Graphics character set
  • "Graphic renditions" (bold, blinking, underline, reverse)
  • 80 or 132 column VT100 display mode
  • Full support for VT100 line-drawing
  • User defined "renditions" (replacing bold with color)
  • Double-height and double-width rendition
  • Extended F-key mode
  • Color mode

Other features:
  • Modern UI with multiple sessions in tabbed window
  • Full keyboard remapping
  • Scripting and recording of VT100 sessions
  • Other Emulations: xterm, VT220, VT420, TN3270, TN5250
  • Small memory footprint (RAM and hard drive)
  • Administrator friendly with easy deployment
ZOC Terminal Emulation Screenshots
Read more about our ZOC terminal emulator, check its extensive list of features and terminal emulations (e.g. xterm, VT220, TN3270, ...) or look at ZOC's screenshots.
Or just go ahead and try it. Start your free 30 days of evaluation today and download ZOC Terminal V8.08.6 now.
ZOC for Windows (32-bit)

Overview: Servers are central computers that can be located anywhere in the world. To use or maintain them, they need to be accessed through so-called dumb terminals or thin clients or PCs running a terminal emulation, e.g. VT102, VT220, Wyse.

The VT100 terminals originate in past when DEC (Digital Equipment) was a renowned manufacturer of mainframes and when VT100 terminals were used to access these servers. Nowadays terminals are emulated (simulated) by software, hence software that takes the function of those VT100 terminals is now called a VT100 emulator.

In other words: A VT100 terminal emulator is software that replicates the functionality of a DEC VT100 terminal, a popular text-based terminal from the 1980s. It allows modern computers to emulate the behavior of the VT100, enabling users to interact with command-line interfaces and text-based applications.

Such software (like ZOC Terminal) is available on Windows or Mac and other operating systems.





Table of Contents


Background of VT100 Emulation/Emulators

In computing, a DEC VT102 (or DEC VT100, which is nearly the same) is a pretty reliable standard terminal type for access to a variety of computer systems.

VT100 and VT102 were introduced in 1978 by DEC, a former competitor of IBM and maker of computer equipment and mainframe computers. It was originally sold as a physical stand-alone terminal for the VAX mainframes.

In the past (before the PC), a VT100/VT102 terminal was to be a device consisting of a physical screen and keyboard. The terminal was connected to a central server and provided a user with the means to enter data into the server and see results that the server sent back to the user's screen. Thus the users had (rather inexpensive) terminals on their desk to provide them with shared access to a (prohibitively expensive) central computer.

However, with todays PCs, the use of a single purpose screen and keyboard to access a server has become an outdated concept. Instead, these days a program on a PC can, emulate (simulate) the functions of a VT100 terminal. A software that does this, is called a terminal emulator.

VT100 Technical Details and Esc-Squences

As all terminal types, VT100 is a standard that allows the server to send text to the user's screen. By embedding special controls in the text, rather than just displaying text from left to right and top to bottom, these codes also allow control over the placement and display charachacteristics (location, color, etc.) of the text.

The VT100 terminal (or emulator) interprets escape sequences and control codes used by the original terminal, providing a user-friendly interface for accessing remote systems or running text-based programs, preserving compatibility with legacy applications and systems.

For example, in order to send the text "This is an error!" to the user's screen with the word "error" highlighted, the host would send  This is an ^[1merror^[0m!  to the VT100 or VT102 terminal. Rather than displaying all the text, the VT100 or VT102 terminal will interpret ^[1m  and ^[0m  as commands that tell it to highlight the text that is received between them, so the output would be:
This is an error!.

Here is a list of basic VT100 control codes:

ESC [ H → Move cursor to top/left position on screen
ESC [ n @ → Insert n (Blank) Character(s)
ESC [ n A → Cursor Up n times
ESC [ n B → Cursor Down n times
ESC [ n C → Cursor Forward n times
ESC [ n D → Cursor Backward n times
ESC [ n m → Set text attributes ( n= 1 → highlight; n=5 → blink, n= 7 → inverse )
(ESC equals character hex 1B or ^[ )

A fulll list of terminal emulation sequences for VT100 can be found in the VT100 User Guide on vt100.net.

Testing a VT100 via vttest

The quality of a terminal emulator can be measured by testing how fully it implements the terminal emulation sequences (see above) and how closely its matches the original terminal's behavior in borderline situations (i.e. when it receives unexpected, faulty or weird combinations of sequences).

Vttest is an application that is used to demonstrate features of VT100 and related terminals, or emulations thereof, such as xterm.

ZOC has been tested using the vttest suite, based on a test score developed by Columbia University. ZOC Terminal has scored an excellent 105 Points (see the full report), which ranks it among the best in the industry.

ZOC Terminal: Modern VT100 Emulation for Windows and macOS

Today most 'terminals' are simply a software running on a PC. But many standard telnet clients can be used to emulate VT100 terminals in a basic way, but lack support for certain subtleties in the way true VT100 terminals handled the incoming data. Essentially, the basics of VT100 are easy to implement, which is why it is supported in most terminal software to some extent, but the subtleties are hard to get right.

ZOC however is different, it lets you access mainframes via a telnet or SSL/SSH v2 connection using an expertly built VT100 emulation. Additionally ZOC supports a wide scale of other emulations used in the Unix world, like Linux, xterm, VT220, TN3270, TN5250, Wyse, QNX, etc.

The ZOC telnet/SSH client also includes a number of other useful features. It comes with a modern multi-tabbed user interface and is highly configurable. Beyond that it includes the usual terminal features such as keyboard redefinition and scroll back buffer. It also has some very advanced and unique features such as a powerful script language and automatic triggering of actions based on received or typed text. This terminal emulation software also supports vt102, vt220 and several types of ansi as well as Wyse, TVI, and Sun's CDE. ZOC also features major file transfer protocols like X-, Y- and Zmodem as well as Kermit and others. All these are offered in solid implementations that leave nothing to be desired.





ZOC Terminal Download

Read more about our ZOC Terminal Emulator, check its feature list, look at our screenshots or start your free 30 days of evaluation today and download ZOC Terminal V8.08.6 now.

ZOC for Windows (32-bit)


Terms of Use
Privacy Policy