connect to a comma 3/3X

A comma 3/3X is a normal Linux computer that exposes SSH and a serial console.

Serial Console

On both the comma three and 3X, the serial console is accessible from the main OBD-C port. Connect the comma 3/3X to your computer with a normal USB C cable, or use a comma serial for steady 12V power.

On the comma three, the serial console is exposed through a UART-to-USB chip, and tools/serial/connect.sh can be used to connect.

On the comma 3X, the serial console is accessible through the panda using the panda/tests/som_debug.sh script.

SSH

In order to SSH into your device, you'll need a GitHub account with SSH keys. See this GitHub article for getting your account setup with SSH keys.

  • Enable SSH in your device's settings
  • Enter your GitHub username in the device's settings
  • Connect to your device
    • Username: comma
    • Port: 22

Here's an example command for connecting to your device using its tethered connection:
ssh comma@192.168.43.1

For doing development work on device, it's recommended to use SSH agent forwarding.

Notes

The public keys are only fetched from your GitHub account once. In order to update your device's authorized keys, you'll need to re-enter your GitHub username.

The id_rsa key in this directory only works while your device is in the setup state with no software installed. After installation, that default key will be removed.

ssh.comma.ai proxy

With a comma prime subscription, you can SSH into your comma device from anywhere.

With the below SSH configuration, you can type ssh comma-{dongleid} to connect to your device through ssh.comma.ai.

Host comma-*
  Port 22
  User comma
  IdentityFile ~/.ssh/my_github_key
  ProxyCommand ssh %h@ssh.comma.ai -W %h:%p

Host ssh.comma.ai
  Hostname ssh.comma.ai
  Port 22
  IdentityFile ~/.ssh/my_github_key

One-off connection

ssh -i ~/.ssh/my_github_key -o ProxyCommand="ssh -i ~/.ssh/my_github_key -W %h:%p -p %p %h@ssh.comma.ai" comma@ffffffffffffffff

(Replace ffffffffffffffff with your dongle_id)

ssh.comma.ai host key fingerprint

Host key fingerprint is SHA256:X22GOmfjGb9J04IA2+egtdaJ7vW9Fbtmpz9/x8/W1X4
+---[RSA 4096]----+
|                 |
|                 |
|        .        |
|         +   o   |
|        S = + +..|
|         + @ = .=|
|        . B @ ++=|
|         o * B XE|
|         .o o OB/|
+----[SHA256]-----+