Most phone systems allow you to make paging announcements through speakers in the phones. But if you want to reach people in places where there are no phones, or in a noisy area, you'll need a separate paging amplifier and speakers. Most amplifiers can be connected to your phone system with an inexpensive patch cord. Some can also handle background music and a microphone.
Here are some general guidelines for choosing equipment:
Figure that one speaker can cover a radius of about 20 feet in a "normal" environment.If the ceiling is higher than 12 feet, or the environment is very noisy, the coverage radius will probably be about 10 - 15 feet.It's tempting to try to increase coverage (and use fewer speakers) by increasing the volume, but this can be uncomfortable, and unhealthy, for people near a speaker.Most paging speakers are very efficient, and don't need much power to reach full volume.Figure on about 5 - 10 watts per speaker. A 15-watt amplifier should be fine for two or three speakers.If the distance from amplifier to speaker is more than about 100 feet, provide a few more watts.We recommend that you use 18-gage stranded SHIELDED speaker wire. It's near the bottom of the page.