2 Button. This Videx 3112A full base audio phone has an adjustable electronic call tone, a door open push button, a spare service button and privacy switch. It is suitable for use on traditional 4+1 audio systems that require an electronic call tone including the 4k series, 8K series, VR4K series and VR120DK series kits. . 3 position call tone adjustment. 2 position privacy switch (ON/OFF). Spare service button. Door release facility