Using veetee

The window

The terminal page is drawn like a DEC CRT, with the proportions of the model's screen, pixel fonts, dot stretching and scan lines. The window menu has:

• Phosphor — white (P4), green (P1) or amber (P3); --phosphor chooses it at start
• Screen — Glow, Afterglow, Curved Screen and Visible Bell (see below)
• Set-Up — the terminal's Set-Up screens, as F3 (see Set-Up)
• Open Second Session — a second connection to the same destination (see below)
• Close Session — closes the session the keyboard is in, leaving the other the whole window
• Mark Checkpoint — a named point in the session recording (see Connections)
• Keyboard Map… — the keymap editor (see Keyboard)
• Full Screen
• About veetee

CRT effects

The Screen section of the window menu switches the effects, and veetee remembers the choice (appearance.conf in the configuration directory):

• Glow (on) — a soft halo of light around lit dots.
• Afterglow (on) — lit phosphor fades out rather than switching off at once, for as long as the phosphor's persistence: briefly for P4 white, longer for P1 green and P3 amber.
• Curved Screen (off) — the picture bends like the face of a tube, darker in the corners.
• Visible Bell (off) — "Bell" flashes on the status line when the bell sounds.

Scan lines and dot stretching are always drawn. On a slow or software-only OpenGL, turning Glow, Afterglow and Curved Screen off makes drawing cheaper.

The CRT saver blanks the screen when nothing has been typed or received for a while — 30 minutes on a VT420, or the time the host chose on a VT500 — if CRT Saver is on in Global Set-Up. Any key wakes it (that key is not sent).

Sound

• Keyclick — a short 2 ms beep for each key that sends something or acts.
• Warning bell — a 125 ms beep when the host sends BEL.
• Margin bell — the same beep when typing brings the cursor eight columns from the right margin (off at the factory).
• Tones — VT520 hosts can play notes C5 to C7 (DECPS); they play one after another.

The volumes (high, low or off) are in Keyboard Set-Up, and hosts can change them. Sound uses the default audio output; without one, the desktop bell stands in for the warning bell.

Scrolling

With smooth scroll (Display Set-Up, or the host's DECSCLM), each line glides into place at DEC speed — Smooth-2 at nine lines a second, Smooth-4 at eighteen — and output from the host waits meanwhile, just as a real terminal holds the host back with flow control. A VT420 and VT510 power up in smooth scroll, as their manuals document; the VT520 and VT525 in jump scroll. For fast output (long TYPE or DIRECTORY listings) choose Jump Scroll in Display Set-Up and Save.

Fonts and screen proportions

Each model family draws with fonts on its own character cells, like the hardware:

Models	Screen	80 columns	132 columns
VT52, VT100, VT102, VT220	4:3; each dot row is two scan lines	10×10 dots	6×10 dots
VT320, VT420, VT510, VT520, VT525	800×400 pixels of 1:1.4; one scan line per dot row	10×16 dots (24 lines), 10×10 (36 lines), 10×8 (48 lines)	6×16, 6×10, 6×8

The VT420 cell sizes are those of EK-VT420-RM table 5-5. The 10×16 and 6×16 fonts are drawn by hand and cover DEC Special Graphics, Supplemental and Technical, ISO Latin-1, Latin-2 and Latin-5, Turkish, Greek, Hebrew and Cyrillic in both widths. 36-line screens use the 10×10 font, and 48-line screens hand-drawn 10×8 and 6×8 ASCII; other characters on the smaller cells are resampled from the larger fonts so that separate strokes stay separate. 132-column mode switches to the narrow font rather than squeezing the wide one, and a 36- or 48-line screen keeps the page width and uses shorter cells.

Double-width and double-height lines are drawn by doubling dots, and soft fonts (DECDLD) are drawn from the host's own dot patterns.

The VT525 model draws in colour; the host can assign normal and alternate text colours and load its own 16-colour map. Hosts can also choose a blinking or steady, block or underline cursor (DECSCUSR) and name the session: a VT520 session name (DECSWT) becomes the window title.

Sessions

Like a VT520 with its sessions on different communication lines, a veetee window holds more than one session, each with its own connection and its own terminal state: pages, character sets, UDKs, soft fonts, status line and Set-Up. A VT520 or VT525 has four (S1 to S4), a VT420 or VT510 two, and earlier models one. From 1.8.0.

• New Session in the window menu asks where the session connects: this window's connection, or any saved connection, so one window can hold, say, Telnet, SSH, LAT and a serial line. The session keeps the window's model. --sessions N opens N to the window's connection.
• Two on the screen at once, as on a VT520: the active session and the one active before it, split horizontally with a title bar each. The rest keep running, out of sight.
• F4 (the Session key) moves to the next session, S1 → S2 → S3 → S4; Alt+1 to Alt+4 go to one directly, as Caps Lock with keypad 1–4 on a VT520. Clicking a session's screen makes it active too, and a host can with DECES.
• Ctrl+F4 switches between one window and two, as Ctrl+Session does, and Ctrl+Shift+Up and Down move the line between the two; it stays where you leave it.
• Session icons: with more than one session, a row of icons above the windows, one per session, named by the host (DECSIN) or from the session's name. The active session's is raised; one out of sight whose host has sent something turns orange and blinks until you look; clicking an icon goes to that session. Framed windows in Display Set-Up (DECFWM), on by default, turns the title bars and icons on and off.
• Each session's Set-Up is its own, saved as setup-vt520-session3.conf and so on.
• Close Session in the window menu closes the active session, and the one before it takes its place. With a single session open it says so and does nothing: that session is the window. A session that ends by itself does the same, with the reason shown as a notification; a single session's screen is kept instead, marked Disconnected, so that it can still be read and copied.
• Several sessions over one line (TD/SMP, with SSU on the host) are not provided.

Status line

Below the page is the VT420 indicator status line, in reverse video. From left to right it shows the printer state, Hold Screen while output is held, Locked while the keyboard is locked, the page number and the cursor position (line, column).

Host applications can replace it with a host-writable status line (DECSSDT/DECSASD), as DECforms and some SMG$ applications do.

Screen size and page memory

The VT420 model has page memory: six 24-line pages by default. A host can select 25, 36, 48, 72 or 144 lines per page, and 24, 36 or 48 lines on the screen. When the page is longer than the screen, the view follows the cursor (DECVCCM), and SU/SD pan through the page as on a real VT420. Ctrl+↑ and Ctrl+↓ pan the view yourself; Ctrl+End and Ctrl+Page Down look at the previous and next pages.

Hold Screen

F1 or Pause toggles Hold Screen. veetee stops reading from the host, so flow control holds the output back without losing any of it. Press the key again to continue.

Copy and paste

• Drag to select. Double-click selects a word — VMS file specifications such as DKA0:[SYS0.SYSCOMMON]LOGIN.COM;1 count as one word. Triple-click selects a line.
• A selection goes to the primary selection, so middle-click pastes it.
• Ctrl+Shift+C copies to the clipboard; Ctrl+Shift+V pastes.
• Both are also on the right-click menu.

DEC line-drawing and special characters are copied as their Unicode equivalents. Lines that were joined by autowrap are copied without a line break. Text can be selected in the history too, and a selection stays with its text as output scrolls.

Pasted text is sent as if typed, through the character sets the host is using. Line breaks become Return, tabs are kept and other control characters are dropped. Characters those sets cannot send are replaced by the nearest they can: typographic quotes, dashes and … by ASCII, accented letters without an encoding by the plain letter (ł by l), € by EUR, and anything else by ?.

History and search

Lines that scroll off the top of the page are kept (10,000 of them). The mouse wheel or Shift+PgUp and Shift+PgDn move the screen back through them, as a VT520 reviews previous lines. Typing, or new output from the host, returns to the page.

Find… in the window menu (Ctrl+Shift+F) opens a find bar over the terminal. It searches the history and the page, ignoring case, newest first: Enter finds the next older match, Shift+Enter the next newer, and Esc closes the bar. Each match is highlighted and brought onto the screen, and it stays in view while output continues.

Accessibility

Screen readers such as Orca see the terminal as a terminal named "Terminal". They can read the lines on the screen — or Set-Up, while it is open — word by word or line by line, and the caret follows the cursor. New output and typed characters are announced as they appear: when the screen scrolls, only the new lines are reported, not the whole screen.

Answerback

Ctrl+F5 (or Ctrl+Break) sends the answerback message.

Not yet available

Several sessions over one line (TD/SMP), Sixel and ReGIS graphics, the Tektronix modes, XMODEM, YMODEM and ZMODEM, and the few Set-Up settings listed under What takes effect in Set-Up. Printing (from 1.5.0, Printing), Kermit file transfer (from 1.3.0, File Transfer), a serial line set from Communications Set-Up (from 1.6.0, Connections) and four sessions (from 1.8.0) are all available.