Actually, many larger veunes are using a digital system to handle their paging. An operator may simply key in the message, upload it to the paging controller, and then the page goes out one or more of several synthesized languages. Some of these systems can be preprogrammed to make announcements at certain points in the day (you didn't really think the "white zone is for loading and unloading only" announcement went out live each time, did you?) and with airports and train stations offering the same schedule day after day, it makes sense. In the U.S. and many other parts of the world, the Media Matrix and IED lines operate in a vast number of Airports and stations.
http://mm.peavey.com/products/controlmatrix/chost.cfm
Air-Geko