Do I need X Windows to use the ToolTalk service?

The ToolTalk service does not use X messages or protocols to deliver messages. The ToolTalk service is only associated with X Windows if you run an X session.

When you run an X session, the session name is advertised as a property (named TT_SESSION) on the root window of the X server. Every process which names that X server as its display gets that X session as its default session. Since the X session is defined to be the group of processes displaying on a particular X display, you do need to run X Windows by definition but not because the ToolTalk service requires you to use it.

If there is no X server running at all (for example, you are running a session that consists entirely of character-mode applications running on a dumb terminal), use a process tree session. When you run a process tree session, the session name is advertised in the environment variable TT_SESSION. This session is the default session for every process in the tree of processes descending from the process that set the environment variable.