Wireless DECT handsets are used by staff for a range of system features – including telephony, duress alarms, public address, and to initiate DVA announcements. Operation requests are directed to and from local Gateway units where they are controlled and managed. Gateway units can also contain real time database information (such as service timetable data) which can be accessed and updated via the wireless handsets. Real time data is passed to and from the database via the Communications Exchange.