VT05
| Industry | Computer hardware |
|---|---|
| Founded | 1957 |
| Headquarters | United States |
| Products | VT05 computer terminal |
The VT05 represents Digital Equipment Corporation's inaugural standalone CRT computer terminal, introduced in 1970. Recognized for its unique aesthetic, it presents upper-case ASCII characters arranged in a 72-column by 20-row format. As an intelligent terminal, it enables cursor movement through control characters, including absolute positioning on the display. This early model laid the groundwork for the subsequent VT50 and VT52 terminals.
This terminal supports only forward scrolling and direct cursor positioning but does not include sophisticated editing capabilities or visual text effects such as blinking or underlining. It operates with asynchronous communication at speeds up to 2400 baud, necessitating fill characters when exceeding 300 baud.
Inside, the VT05 incorporates four "quad-sized" DEC modules mounted horizontally on a standard DEC backplane above the CRT display. Its physical dimensions are 19 inches in width and 30 inches in depth, making it larger than most desk terminals of its time.
Initially, the keyboard employed advanced capacitive sensing technology; however, this was later replaced by simpler mechanical switches due to issues with reliability.
The terminal’s dynamic memory utilizes a PMOS shift register architecture, which requires fill characters after each line feed—a design differing from contemporary hard-copy terminals.
Furthermore, the VT05 can serve as a black-and-white RS-170 video monitor, accepting input from videotape recorders and cameras. It is capable of overlaying text onto video signals, facilitating interactive uses.
Following the VT05, Digital Equipment Corporation introduced the VT50, which was soon succeeded by the more feature-rich VT52 model.
Commands
The VT05 implements a concise range of commands:
| Decimal | Control Char | ASCII | VT05 name | Function |
|---|---|---|---|---|
| 7 | ^G | BEL | BELL | Emits a 266 ms audible tone at 780 Hz (G5). |
| 8 | ^H | BS | C← | Moves the cursor one position to the left. |
| 9 | ^I | HT | TAB | Advances cursor to the next tab stop, set every eight characters. |
| 10 | ^J | LF | LF | Moves cursor down one line; scrolls if at bottom line. |
| 11 | ^K | VT | C↓ | Moves cursor down by one line. |
| 13 | ^M | CR | CR | Returns cursor to the beginning of the current line. |
| 14 | ^N | SO | CAD | Direct cursor addressing: positions cursor at specified row and column. |
| 24 | ^X | CAN | C→ | Moves cursor one position to the right. |
| 26 | ^Z | SUB | C↑ | Moves cursor up one line. |
| 29 | ^] | GS | HOME | Sends cursor to upper-left corner of screen. |
| 30 | ^^ | RS | EOL | Erases from current cursor position to end of line; cursor remains fixed. |
| 31 | ^_ | US | EOS | Erases from current cursor position to end of screen; cursor remains fixed. |
To clear the display, send HOME followed by EOS commands.