Access: 1A2 Intercom Station Electronic or 1A2 Line Key, PBX Loop Start Trunk Port, Page Port on Selected Telephone systems, or Dedicated Single Line Phone Set; Specifications: Input Impedance: 600 ohm; Music Source Impedance; 4 to 600 ohm; Music Input Level: -10 dBm nominal; Power Requirements: -24 Vdc, 150 mA (Filtered) 10 Vac Lamp; Shipping Weight: 2.8 lbs (1.27 kg) Dimensions: 7.1" H x 5.9" W x 2.1" D (18.03 cm x 14.98 cm x 5.33 cm)