Sentinel 4, Full Specification Entryphone As part of the Sentinel 4 door entry system this elegantly styled entry phone offers the following features Electronic call tone Impact resistant plastic molding Full, clear, duplex speech Door monitor, (green LED) Privacy mode,(red LED) Timed privacy facility (0.5 -16 hrs) Clear instruction label adhered to phone screw terminal outputs for extension beacons or sounders. Optional desk mount kit Operates on a common 4 wire bus, ideal for system upgrades.   Dimensions Height 212mm Width 86mm Depth 65mm Colour Light Grey