Monitor Switch

A lightweight macOS and Windows utility for switching monitor inputs from the menu bar or system tray. It sends DDC/CI VCP 0x60 commands directly, so normal use does not require BetterDisplay, ddcctl, ddcutil, or ControlMyMonitor.

Monitor Switch is deliberately small: inputs switch only when you choose an input or press a configured shortcut. Display discovery updates on connection and wake events. There is no USB listener, cloud service, account, analytics, or background polling.

Features

• Built-in DDC/CI on macOS and Windows
• Native macOS menu and native Windows system-tray menu
• One-click switching between named inputs
• Optional global shortcuts for individual inputs and switching back
• Independent previous-input history for each display
• Multiple monitors with independent input names
• Per-input control over which sources appear in the tray menu
• Input commands without an inferred current-source checkmark
• CLI for discovery, diagnostics, and scripts
• Compatibility backends for unusual monitor, dock, and GPU combinations
• Starts at login on macOS after installation
• Optional per-user startup shortcut on Windows
• Single-instance startup: opening the app again shows the existing Settings
• Display rediscovery after connection changes and wake

Requirements

• A monitor with DDC/CI enabled in its on-screen settings
• macOS 12 or later, or Windows 10/11
• A connection path that carries DDC/CI; some docks, adapters, and KVMs block it

Nintendo Switch and other source devices do not need any software. The Mac or PC running Monitor Switch sends the command to the monitor.

macOS installation

Until signed release artifacts are published, build and install locally:

./scripts/install-macos-app.sh

This installs Monitor Switch.app in ~/Applications, registers a per-user login item, and starts it without a Terminal window. Open it later from Finder, Launchpad, or Spotlight like any other application.

Build without installing:

./scripts/build-macos-app.sh
open "dist/Monitor Switch.app"

Windows installation

On Windows 10/11, open PowerShell in the repository and run:

powershell -ExecutionPolicy Bypass -File .\scripts\install-windows.ps1

This installs the app in %LOCALAPPDATA%\Programs\Monitor Switch, creates a per-user Startup shortcut, and opens it directly in the system tray without a console window. The settings window uses the Windows WebView2 runtime included with current Windows 10 and Windows 11 installations.

Build a portable ZIP without installing:

powershell -ExecutionPolicy Bypass -File .\scripts\build-windows.ps1

The archive is written to dist\Monitor-Switch-Windows.zip and contains one user-facing executable, Monitor Switch.exe. The diagnostic CLI remains available to developers through Cargo but is not included in the user package.

First setup

1. Enable DDC/CI in the monitor's physical on-screen menu.
2. Open Monitor Switch from the menu bar.
3. Open Settings.
4. Give the inputs you use recognizable names, such as Mac mini, Gaming PC, or Nintendo Switch.
5. Save, then select an input from the menu.

Monitor input values are not perfectly consistent between manufacturers. The settings window includes the common MCCS values and keeps custom values already present in the configuration.

DDC/CI can report which inputs a monitor model supports and which input is currently active, but it usually cannot report whether a cable is physically connected to every inactive port. Monitor Switch shows inputs reported by the monitor by default, keeps generic fallback candidates hidden, and lets every input be shown or hidden in Settings.

Keyboard shortcuts and switching back

Settings includes a shortcut recorder below each input name and a separate recorder for returning to the previous input on that display. Focus a recorder, press a combination containing Control, Alt/Option, or Command/Win, and save. Use the clear button or Delete/Backspace to remove a binding. No shortcuts are assigned by default. Duplicates and system registration conflicts are reported without replacing the existing saved bindings.

The menu's 切回 action uses per-display history from successful reads and accepted switch commands. History lasts for the current app session; a command being accepted is not a guarantee that the monitor physically switched. Before returning, the app reads the current input again; if that read fails, it does not guess or send a switch command. Shortcuts work while the app is running and the computer can communicate with the monitor, including when the tray menu is closed.

CLI

# Discover displays and stable selectors
monitor-switch displays

# List common input values
monitor-switch candidates

# Read a display's current input
monitor-switch current --display 1

# Try a value without saving it
monitor-switch raw 0x11 --display 1

# Save and use a named profile
monitor-switch add pc 0x11 --label "Gaming PC" --display 1
monitor-switch switch pc

The configuration path can be printed with monitor-switch config-path. Existing 0.1 configurations remain compatible with 0.2.

The macOS application bundle includes the CLI at Monitor Switch.app/Contents/Resources/monitor-switch. Developers can also run it through cargo run --bin monitor-switch -- <command>.

Input values

Common values include:

Value	Input
0x0f	DisplayPort 1
0x10	DisplayPort 2
0x11	HDMI 1
0x12	HDMI 2
0x13	HDMI 3
0x1b	USB-C / DP Alt Mode

These are common MCCS values, not a guarantee for every monitor model.

Compatibility backends

The default auto backend is the built-in native backend. These explicit values remain available for troubleshooting older setups:

• betterdisplay
• ddcctl
• ddcutil
• control-my-monitor

For example:

monitor-switch raw 0x11 --display 1 --backend ddcctl

Development

cargo fmt --all -- --check
cargo test --all-targets
cargo clippy --all-targets -- -D warnings

See Architecture, Changelog, and Contributing.

Acknowledgements

The native DDC layer builds on the Rust DDC ecosystem used by haimgel/display-switch, especially ddc-hi, ddc-macos, and ddc-winapi. Monitor Switch intentionally focuses on an on-demand menu experience rather than USB-triggered automation.

License

MIT