On board fleet and rollingstock systems typically include a number of remote Gateway units which are located on a LAN. All crew communication is via a Crew Panel and is routed via the Train Communications Exchange. The Gateway units are responsible for queuing and prioritising LLPA and DVA announcements, as well as managing display outputs. Emergency Help Points can be standalone and connected directly to the LAN or controlled by Gateway units.

Wayside communications include data (such as GPS) and even wireless audio options – either via a radio interface or wireless link.