Smart 4-wire Videos

GBF Smart 4 Wire Multi Unit Doorbell Intercom Introduction Video

link="https://www.youtube.com/watch?v=FCwflit7P5g&t=140s

GBF 4 Wire Smart Intercom System Introduction

link="https://www.youtube.com/watch?v=hmpnbWAyQIU&t=384s

GBF 4 Wire Intercom Intro

link="https://www.youtube.com/watch?v=XPV7XKwnXHk&t=17s