Check the listing for details. Viking electronics PI-1A Universal Telecom Paging. Condition: New. Listed at 124.11 USD. Integrate your public address system with nearly any phone system Cut out background music during paging Electronic night bell from ringing line or contact closure Floating 600 ohm output Selectable 22V DC talk battery for interfacing with unused phone system line input/trunk ports Paging port interface Ringing analog line input for night bell Contact closure input for night bell DPDT normally open and normally closed VOX activated contacts for cutting out background music Adjustable VOX contact time-out Adjustable VOX trigger sensitivity Adjustable ring volume Adjustable ring pitch Power: 120V AC/12V DC 500mA, UL listed adapter provided Dimensions: 111mm x 76mm x 36mm (4.38” x 2.97” x 1.38”) Shipping Weight: .48 kg (1.06 lbs) Environmental: 0°C to 32°C (32°F to 90°F) with 5% to 95% non-condensing humidity Relay Contacts: 30V DC@1A, 110V DC@0.3A, 125V AC @0.5 Maximum Ring Output: 490mV AC RMS no load, 150mV AC RMS@600 ohms VOX Minimum Audio Signal to Activate Relay: 30mV AC RMS@1K Hz Talk Battery: 22V DC