4000 Series speaker/microphone unit for 4K audio kits with 1 call button and illuminated name plate. It has separate volume controls for mic and speaker and requires a 12v a/c supply such as the 321 or 322 psu. This unit can be configured for a/c calling or electronic call tone.
Number of buttons – 1
Lock output – Dry contact (C, NO)
Power – 12Vac