KVM Tutorial 03 — Advanced Features

Audience: Intermediate to Expert — power user features and configuration

1. Preferences System

Video

Resolution & frame rate — Preferred capture settings
Media backend — FFmpeg, GStreamer (Linux), or Qt Multimedia (Windows)
Hardware acceleration — VAAPI (Intel/AMD), V4L2-M2M (Raspberry Pi)
Aspect ratio & scaling — Custom ratio, Stretch/Fit/Fill

Audio

Enabled — Toggle audio capture from target
Input/Output device — Select source and playback device

Target Control

Mouse mode — Absolute, Relative (HID), Relative (Events)
Mouse event throttle — 30–1000 events/second
Keyboard layout — Target OS and regional layouts
Repeating keystroke interval — Held key repeat speed
Auto-hide cursor — Hide host cursor over video area

Logging

Log level — Debug, Info, Warning, Error
Log to file — ~/Documents/openterface.log (macOS) or configured path (Qt)
Serial logging — Separate serial communication log

2. EDID Management

What Is EDID?

EDID (Extended Display Identification Data) is what the KVM device sends to the target to describe its display capabilities — supported resolutions, refresh rates, vendor info. The KVM acts as a "fake monitor," so EDID determines what resolutions the target will output.

Editing EDID Display Name

You can change the display name that the KVM device reports to the target. This name appears in the target OS display settings.

Note: Only editing the display name is currently supported. Resolution editing and custom resolution entries are not yet available.

Access: Settings > EDID Display Name Editor (macOS) or Device > Update Display Settings (Qt)

Use Cases

Identifying the display in target OS settings
Custom naming in multi-monitor setups to distinguish the KVM display

3. Macro System (macOS)

Macros are saved keyboard action sequences triggered from the toolbar macro panel.

Key Sequence Format

Modifier Tags: <CTRL>, <SHIFT>, <ALT>, <CMD> (maps to Cmd/Win/Super depending on target OS)

Special Keys: <ESC>, <BACK>, <ENTER>, <TAB>, <SPACE>, <LEFT>, <RIGHT>, <UP>, <DOWN>, <HOME>, <END>, <DEL>, <PGUP>, <PGDN>, <F1>–<F12>

Delays: <DELAY05s>, <DELAY1S>, <DELAY2S>, <DELAY5S>, <DELAY10S>

Examples

Text Only

<CMD>c</CMD>              # Copy on macOS
<CTRL>c</CTRL>            # Copy on Windows
<DELAY05s><ENTER>         # Wait, then press Enter

AI-Assisted Generation

The macro editor's Magic button generates macros from natural language. Describe what you want and the AI produces the key sequence.

Verification

Mark macros as verified after testing. Only verified macros are available to the AI agent for autonomous execution.

4. Script Tool (Qt)

An AutoHotKey-inspired scripting language for automating keyboard and mouse actions on the target.

Opening

Menu: Device > Script Tool

Commands

Command	Description	Example
`Sleep`	Pause execution	`Sleep 1000`
`Send`	Send keystrokes	`Send Hello World`
`Click`	Mouse click	`Click 100 200`
`SetCapsLockState`	Toggle CapsLock	`SetCapsLockState On`
`FullScreenCapture`	Screenshot	`FullScreenCapture "/tmp/shot.png"`

Modifier Prefixes

^ = Ctrl, + = Shift, ! = Alt, # = Win

5. Firmware Updates

When to Update

New hardware features
Bug fixes
Compatibility improvements

Update Process

Open Firmware Update Tool (Settings > Firmware Update Tool on macOS, Device > Update Firmware on Qt)
The tool checks for the latest version from the network
Progress is tracked during the write operation
Do not disconnect the device during update

Recovery

Keep the device powered
Close and reopen the Firmware Update Tool, retry
Use the Serial Reset Tool if the device is unresponsive

6. Serial Reset Tool

Access: Settings > Serial Reset Tool (macOS) or Device > Factory Reset HID Chip (Qt)

Use when: - Device is in an unknown state after failed firmware update - HID chip is not responding - Preparing the device for resale

7. Diagnostics (Qt)

Menu: Device > Device Diagnostics

Runs hardware tests sequentially: 1. Serial connection test 2. Target USB status 3. Factory reset test 4. High/low baudrate test 5. Stress test (rapid commands, measure success rate) 6. Plug & play test (USB disconnect/reconnect detection)

After running, export results via the Support Email Dialog.

8. AI Chat System (macOS)

Built-in AI assistant that can analyze the target screen, suggest actions, and execute keyboard/mouse operations.

Chat Modes

Mode	Description
Interactive	Ask questions, get guidance
Agentic	AI autonomously plans and executes multi-step tasks
Guide	One instruction at a time, step by step
Planner	Complex requests broken into structured plans

Configuration

Settings > AI Chat: API endpoint, key (stored in Keychain), model, target system (macOS/Windows/Linux/etc.)

9. Remote Control (VNC/RDP — macOS)

Switch between Hardware KVM, VNC, and RDP modes via Control > Connection Protocol.

Scenario	Mode
Target in BIOS/UEFI, no network, booting, crashed	Hardware KVM
High-bandwidth desktop use, Windows server	VNC or RDP

10. TCP Server (Qt)

Built-in TCP server for remote control on port 12345.

Commands

CHECK_STATUS, GET_LAST_IMAGE, GET_TARGET_SCREEN, SCRIPT_COMMAND

Python Example

Python

import socket
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect(("localhost", 12345))
sock.send(b"CHECK_STATUS\n")
print(sock.recv(4096).decode())
sock.close()

Security: No authentication, encryption, or rate limiting. Only enable on trusted networks.

iPadOS-Specific Features

Bluetooth Connection Management

The iPadOS app connects to the KVM-Go dongle via Bluetooth Low Energy (BLE) for keyboard/mouse HID input:

Auto-connect: Enabled by default. On startup, the app scans for 5 seconds and auto-connects to the kvm* device with the strongest signal.
Reconnection: If the connection drops, the app attempts to reconnect up to 3 times with a 2-second delay.
Signal monitoring: RSSI updates every 2 seconds. The BLE button shows the signal strength (e.g., -45 dBm) with a color indicator: green (-50 to 0 dBm), orange (-70 to -50 dBm), red (below -70 dBm).
Device scanning: Only devices whose name starts with kvm (case-insensitive) appear in the list.
Manual control: Open the BLE screen to scan, connect, disconnect, or disable auto-connect.

Info Overlay

Tap the Info button to display a real-time input status overlay in the top-right corner:

Text Only

┌─ Input Status ────────┐
│ Mouse                 │
│ Mode: Absolute        │
│ Position: 512.0, 384.0│
│ Drag Mode: Active     │
│ Scrolling: Inactive   │
│ Keyboard              │
│ Mode: Normal          │
│ Caps Lock: OFF        │
│ Modifiers: Ctrl, Shift│
└───────────────────────┘

The overlay is transparent to touches — it doesn't block interaction with the video preview.

Screen Orientation Correction

Tap the Rotate button to cycle through orientation correction modes: Normal, 90° CW, 180°, 90° CCW. This corrects the video preview when the KVM-Go dongle is mounted in a non-standard orientation. Rotation applies to both live preview and saved captures.

Idle Timer Disabled

The app keeps the iPad screen awake during use by disabling the idle timer, preventing the iPad from auto-locking while monitoring the target PC.

Logging System

The app includes a built-in Logger with category-based filtering:

Category	Covers
`bluetooth`	BLE scanning, connection, data transmission
`mouse`	Mouse input, gesture detection, mode changes
`keyboard`	Key events, modifier state, composite keys
`camera`	Video recording, screenshots, photo capture
`ui`	Touch handling, gesture recognition, preview layer
`general`	App lifecycle, general info

Logging can be adjusted in the app source to reduce console noise.

Next Steps

Troubleshooting → — Common problems and solutions

Android-Specific Features

Settings Panel

The Android app's settings panel (Menu button ☰) contains all configuration options:

Setting	Description
Device	Shows connected USB devices and status. Tap to select or re-scan.
Disconnect Device	Safely releases all USB connections. Use before unplugging.
Baudrate	Serial communication speed: 115200 (default) or 9600 (slower, for issues).
Controls	Camera brightness, contrast, and hue sliders.
Video Format	Resolution and frame rate selector.
Rotate/Flip	Rotate 90° CW/CCW, flip horizontally/vertically.
Screen Capture / Record Video	Screenshot and video recording.
Relative / Absolute / Drag	Switch mouse control mode.
About Device	Shows Android version and app version info.

Settings Persistence

The Android app remembers your preferences between sessions:

Setting	Persisted?
Mouse control mode	Yes
Video format (resolution, FPS)	Yes
Camera parameters (brightness, contrast, hue)	Yes
Keyboard layout (US, JP, DE)	Yes
Baudrate	Yes
Device connection history	Yes

When you reopen the app, it restores your last settings. To reset everything: Android Settings → Apps → Openterface → Storage → Clear Data.

Safe Disconnect

Before unplugging the KVM device on Android:

Open the settings panel
Tap Disconnect Device (shown in red)
Wait for the app to release the USB connection
Unplug the cables

This prevents data corruption and ensures the target computer properly releases the keyboard/mouse.

Android Performance Tips

Lower the resolution — 640×480 is much lighter than 1920×1080
Reduce the frame rate — 30fps uses less bandwidth than 60fps
Close other apps — free up your phone's memory
Use a quality USB OTG adapter — cheap adapters can bottleneck the connection
The development team is working on reducing latency in the camera pipeline itself