How remote control works
Remote control lets a tuner read and write an ECU that is connected to somebody else's laptop, anywhere, with the car owner confirming each operation.
Two roles
| Role | Who | What it does |
|---|---|---|
| Server | The tuner | Runs the full FastECU. Its Read ROM, Test Write ROM and Write ROM buttons run on the Client's ECU instead of on local hardware. |
| Client | The person with the car | Has the cable or adapter plugged into the car. Runs either the full FastECU in the Client role, or the small Remote Client. |
Both roles need an active FastECU subscription in the full app. The small Remote Client needs none of its own; only the Server needs one.
How the two are connected
- Both sides connect to a broker, a small relay. You can use the FastECU hosted broker, or run your own (the
FastECU-v2-brokerproject, with Node or Docker). - The Server starts a session and gets a short token (for example
ABCD-1234) that it gives to the Client, by voice or in a chat. - The Client enters the token and both dial the broker.
What is protected
- The link between the two FastECU instances is end-to-end AES-256-GCM encrypted, keyed from the token. The broker only sees the token (to route it) and never the ECU commands or ROM data.
- The hosted broker only relays for tokens that a licensed Server registered.
- The only thing that passes through this website is a short token handshake. The read and write traffic never does.
- A write's ROM bytes travel to the Client but are never put into the Client's ROM list or Calibration page. The Client sees only that a write happened. A read shows up on both sides, because getting the ROM back to the Server is the point.
What the Client has to confirm
- Connecting to the car and listing, opening and closing the Client's ports happen without a prompt, as a local connect does.
- Read, Test write and Write each need the Client to confirm locally first, with the same confirm dialog a local click would show.
- Live progress goes back from the Client to the Server while an operation runs.
Trust the other side
The token is the trust boundary. Only pair with someone you trust, and only give a token to a person you trust: a Server can read and, with your confirmation, write your ECU. Have stable power on the car and a stable internet connection before a remote write.