ZeroTrace Companion
Connecting Devices
How Companion finds, identifies, and connects to ZeroTrace hardware over USB.
Companion talks to your ZeroTrace devices over USB serial. When you plug a device in, the operating system exposes it as a virtual COM port; Companion enumerates the ports, probes each one to figure out what's on the other side, and presents the result in the device picker.
This section covers the connection layer — how it works, how to handle multiple devices, and how to add custom firmware that does not match the standard signatures.
What's in this section
| Page | What it covers |
|---|---|
| Serial ports | What a COM port is, how to find one on each operating system, and what permissions you need |
| Auto-detection | How Companion figures out which ZeroTrace device is on which port |
| Multiple devices | Working with two or more ZeroTrace devices plugged in simultaneously |
| Custom firmware | Configuring Companion to recognise a custom-firmware device that does not match the standard handshake |
The connection lifecycle in 30 seconds
- Plug in a device. OS recognises it as a USB serial device.
- Open Companion. The device picker (top-left) lists every detected port.
- Companion probes each port — sends a quick handshake, listens for a response.
- Each port is labelled with what Companion found: HID, AirLeak, BLE Logger, unknown, busy, or empty.
- Pick a device and click Connect. Companion opens the connection at the right baud rate for that device type.
- The workspace switches to match the connected device — HID dashboard, AirLeak workspace, or generic terminal for unknown devices.
Companion remembers the last connected device. If you plug the same device into the same port, Companion can auto-reconnect on launch — toggle this in Settings → Connection.
What happens when you disconnect
Pulling the USB cable, putting the device to sleep, or clicking Disconnect:
- The port closes cleanly.
- The connected workspace shows a "device disconnected" banner.
- Any unsaved capture data is preserved in memory until you explicitly discard it.
- The picker re-scans and updates.
For unexpected disconnects (cable knocked loose, device crashed), Companion attempts a single auto-reconnect by default. If that fails, you can re-connect manually.
When something goes wrong
The fastest first checks:
- Re-scan ports — Companion's picker has a refresh button, or
Ctrl+R. - Try a different USB cable. Cheap charge-only cables are a common cause of "device not detected."
- Try a different USB port. USB hubs occasionally cause issues; direct connection usually fixes them.
- Check device drivers — see serial ports for the per-OS driver guidance.
- Check for permission errors — Linux users need
dialoutgroup membership.
For deeper troubleshooting see the troubleshooting page.