The most commonly employed terminal nowadays is a virtual (as opposed to real) terminal.
Using the tools in the toolset one can set up services that handle TUI login on virtual terminals, and that provide virtual terminals entirely within application mode code, supplementing or even replacing the virtual terminals provided by a Linux or BSD operating system kernel.
To log on over virtual terminals, kernel or user-space,
one sets up ttylogin
services.
To use kernel virtual terminals one arranges for such services to be enabled and (demand-)started.
Terminals need various resources, some of which are supplied with the toolset.
Using the tools in the toolset one can set up services that handle TUI login on real terminals.
To log on over real terminals
one sets up ttylogin
services.