For decades public address systems have been a useful way to get information to students and staff in K12 and higher education facilities. Most of us can remember hearing morning announcements over the PA or hearing the inevitable call to the front office. It is a great way to convey a message to a group of people. Generally, there are two types of categories that public address systems fall under – paging and intercom. On a basic level, the systems are either one-way communication (paging) or two-way (intercom). In fact, the equipment costs can be about the same depending on.