How can I SSH / get root access to a TLXOS device?

For security reasons, no local user account in TLXOS has a password, including the root account, so it is not possible to access to an interactive root shell by any means that involves password entry.  Passwordless sudo access is tightly restricted to operationally essential commands only, so you cannot get a root shell via sudo either.

The only way that you can get root access on a TLXOS device is via SSH key trust.  This means that before you can SSH to a device, you must use TMS (or Tlxconfig, but TMS is more convenient) to install an SSH public key, and then use the corresponding private key when connecting.  See the TMS USer Manual (http://thinlinx.com/tms-user-manual.pdf) for more information on how to do this using PuTTY.

For convenience, you can right mouse click on a device row in the TMS display and use the provided "SSH to Device" option.  TMS looks for PuTTY (Windows) or SSH in standard locations, and if present will launch it using a profile named "tlxos", so you should create a "tlxos" profile (in PuTTY or ~/.ssh/config) that is associated with the private key that you intend to use and that uses username "root".

To avoid having to constantly re-enter your SSH private key pass phrase, you should also configure Pageant/ssh-agent to load the private key when you log in to the TMS server.  On Windows, you can do this by either creating a shortcut to your PPK file and placing it in C:\Users\<your-username>\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup, or by adding a REG_SZ entry to the HLKM\Software\Microsoft\Windows\CurrentVersion\Run key with the full pathname to your PPK file as its value; either of these will load the key into Pageant.exe via file type association - and prompt you for the pass-phrase, once only - at logon.