Most of the time there is no default password on a new, "blank" Technologic Systems product.  The only user is "root" and there is no password.  This is done so the downstream developer can easily get in and implement whatever security solution they desire without first having to back out the security paradigm used at the time the product was developed.  This strategy also streamlines the downstream developer's efforts once they have entered production and are attempting to process hundreds or thousands (or more) of Technologic Systems single board computers at a time.

There are a small number of exceptions.

SSH does not allow "root" to not have a password.  It will ask for a password anyway, and deny access under all circumstances.  Secure Shell can only be used after an appropriate user has been set up for such usage. 

In our Ubuntu images, the root user does not have a password, but the "ubuntu" user's password is "ubuntu", and the default ubuntu user is already in the superusers (or sudoers) group.  Ubuntu generally frowns on allowing the "root" user as an actual login, preferring all privileged activities be performed by a user with special "sudo" authorization.

On our TS-3000 and TS-5000 series SBCs running Linux, we used a variant of the Redhat distribution:  The default user is 'root' and the password is 'redhat'.

Occasionally we encounter other Linux distributions that developers attempt to use on our SBCs.  Unfortunately we are unable to predict what the default password on those distributions will be.  The best course of action is to contact the publisher of that distribution for more information.

In all cases, Technologic Systems advises implementing a strong security paradigm for your product as soon as possible.