Valcom V-2003A Three Zone One-Way Page Control with Built-In Power, Loop Start, Ground Start, Or Page Port Access, One-Way All Call (One Page to All Zones), Emergency Page Override for Priority Announcements, Unlimited Expansion, Background Music Input, Automatically Mutes In Zone Being Paged, Features Are Programmable Per Zone, Provides Tandem All Call, Page Override For Special, Or Priority Announcements, Built-In Tone Generator For Night Ringing, Time Clock Tone, Door Bell, Accepts Pulse Dial And Tone Dial