VT100

The VT100 is a video terminal, introduced in August 1978 by Digital Equipment Corporation (DEC). It was one of the first terminals to support ANSI escape codes for cursor control and other tasks, and added a number of extended codes for special features like controlling the status lights on the keyboard. This led to rapid uptake of the ANSI standard, which became the de facto standard for hardware video terminals and later terminal emulators. The VT100 series, especially the VT102, was extremely successful in the market, and made DEC the leading terminal vendor at the time. The VT100 series was replaced by the VT200 series starting in 1983, which proved equally successful. Ultimately, over six million terminals in the VT series were sold, based largely on the success of the VT100. DEC's first video terminal was the VT05 (1970), succeeded by the VT50 (1974), and soon upgraded to the VT52 (1975). The VT52 featured a text display with 80 columns and 24 rows, bidirectional scrolling, and a custom control protocol that allowed the cursor to be moved about the screen. These "smart terminals" were a hit due both to their capabilities and to their ability to be run over inexpensive serial links, rather than custom proprietary connections as in the case of systems like the IBM 3270, which generally required expensive controllers for distributed applications. In contrast, "dumb terminals" or "glass teletypes" like the ADM-3A (1976) lacked advanced features such as full cursor addressability, and competed mostly on lowest possible hardware cost. The VT100 was introduced in August 1978, replacing the VT50/VT52 family. Like the earlier models, it communicated with its host system over serial lines at a minimum speed of 50 bit/s, but increased the maximum speed to 19,200 bit/s, double that of the VT52. The terminal provided an option for "smooth scrolling", whereby displayed lines of text were moved gradually up or down the screen to make room for new lines, instead of advancing in sudden "jumps".