The Edwards 5530MD-24AW Adaptatone millennium is a heavy duty industrial, tone selectable, signaling device intended primarily for use in fire alarm systems and other applications requiring electrical supervision of signaling circuit field wiring. It uses a micro-processor circuit to create 55 distinctive tones A single tone may be selected by setting a miniature dip-switch within the unit. The Adaptatone millennium can be activated from field-wired, normally open contacts, or a 24 VDC external voltage source such as an output of a PLC or fire/security panel.