2 Button. This Videx 3102 full base audio phone has an AC buzzer input, adjustable electronic call tone, a door open push button, a spare service button and a privacy switch. It is suitable for use on traditional 4+1 audio systems that require an AC buzzer call or an electronic call tone including the 4k series, 8K series, VR4K series and VR120DK series kits.. 2 position privacy switch (ON/OFF) for the AC buzzer. Spare service button. AC buzzer call. Door release facility