VT100 mode¶

Most serial devices speak in plain lines, and termapy's TUI and CLI handle those well. Some devices emit terminal control beyond plain lines: cursor addressing, full-screen menus, vi or top on an embedded Linux console, BIOS/serial-over-LAN consoles, bootloader UIs. --vt100 is for those.

termapy --vt100 my_device      # raw ANSI terminal on the configured port

Try it without hardware¶

termapy --vt100 --demo

In VT100 mode, --demo connects to a simulated VT100 device (not the line-oriented AT device that --demo selects in TUI/CLI mode). It draws a colored, cursor-addressed UI you drive from the keyboard:

Main menu - Up/Down arrows (or j/k) move the highlighted selection; Enter opens it.
Status dashboard - select Status to drill into a live gauge view that redraws in place; q (or Backspace) returns to the menu.

Quit with Ctrl-]. This is the quickest way to see what passthrough mode buys you over plain line output.

What it does¶

--vt100 drops the TUI entirely and pipes the device straight to your terminal. termapy does not emulate the terminal here - your terminal already is one, so it does the rendering. That keeps it a thin passthrough rather than a UI widget, which is also why it works the same on Windows, macOS, and Linux: the byte pump is the vendored pyserial miniterm, which enables VT processing on Windows 10+ automatically.

It's a peer of CLI and TUI mode, selected the same way:

Flag: --vt100 (overrides the config, like --cli).
Config: "default_ui": "vt100" makes it the default when no mode flag is given.

Precedence is --cli > --vt100 > config default_ui > the tui default.

Switching from the TUI¶

VT100 mode is a reversible toggle from inside the TUI, like /cli <-> /tui:

/vt100 - hand the current device to a passthrough terminal.
/demo.vt100 - jump to the built-in DEMO_VT100 widget tour (see below), whatever device you had loaded.

In both cases Ctrl-] returns you to the TUI, on the same config you left (when launched from the shell with --vt100, Ctrl-] quits the process instead - there's no TUI to return to).

Keys¶

Key	Action
`Ctrl+]`	Exit (or back to the TUI, if entered from it)

Every other keystroke - including Ctrl+T - goes straight to the device. (termapy runs the cross-platform pyserial pump under the hood, but its settings menu is disabled so the session reads as a native termapy view.)

Caveats¶

Needs a VT-capable host terminal. Universal on macOS/Linux; on Windows use Windows Terminal, VS Code, or any Win10+ console. Legacy conhost is unreliable.
Run it in a standalone terminal tab for zero extra key interception. VS Code's integrated terminal adds one layer (the same one any serial terminal faces there) - see Environment & compatibility.
For LLM-driven menu navigation, raw passthrough is the wrong tool. A headless terminal emulator exposed over MCP is the intended path, so the model sends key names and reads a clean rendered screen rather than parsing escape sequences.

When not to use it¶

If the device has a command or JSON API, prefer that (TUI/CLI/MCP). A screen-and-keystroke interface is harder to script and harder to safety-gate than a named-command API. --vt100 is the fallback for interface-poor devices, not the default way to drive hardware.