Bogen ZX3 Expansion Module for UIT312 Telephone Paging AmplifierThe ZX3 provides three zones of telephone paging for the UTI312. Each UTI312 unit comes pre loaded with one ZX3 module and has room for up to three additional modules, for a total of twelve zones. Features: One ZX3 module pre installed with UTI312 3 zones per module Audio output with level control per zone Zone contact closure Zone activity LEDs Pluggable terminal strips