Viking PA-2A Paging / Loud Ringer Amplifier (includes 25AE horn) Amplified loud Paging Loud ringing & Night bell Two watts of paging power Paging is accomplished by connecting the PA-2A to a paging port or unused telephone line input (trunk port) of nearly any phone system The unit comes complete with a power supply, amplifier, and (1) Viking 25AE paging horn