Masterbox : A unit connected to a central fire alarm office that transmits signals from auxiliary or remote alarm stations, fire detection equipment, or automatic sprinkler systems
Ralph W. Burklin & Robert G. Purington, Fire Terms: A Guide to Their Meaning and Use, National Protection Association, Boston, MA 1980 USA. (Guide: Meaning and Use, Nat Prot Association Fr Srvc - Amer) {457}