Compact Steel Ringdown Telephone Overall Depth 2 1/4 in Overall Height 9 in Overall Width 5 in Volume Control Yes Indoor/Outdoor Usage Indoor Standards FCC Part 15 Class A IEC 61000-6-2 2005 Industry Canada ICES-003 Class A Number of Lines 1 Mounting Location Wall Enclosure Material Steel Includes Enclosure Yes Facility Type Commercial Maximum Operating Temperature 140 Degrees F Minimum Operating Temperature -22 Degrees F Color Gray Network Protocol VoIP