Valcom's V-9940 Expandable station level page adapter features Full-Featured Paging From Centrex or Standard C.O. Line, Can Be Use With Valcom Multi-Zone or Talkback Page Controls, Multiple Units can be Linked Together For a Common All Call, UL Listed, Access: Connects Directly to Selected PBX Station Port, Centrex or a C.O. Line(FCC Registered); Specifications: Input Impedance: 600 ohm; Music Source Impedance: 4 to 600 ohm; Music Input Level: -10 to -18 dBm Nominal; Power Requirements: -24 Vdc/200 mA Shipping Weight: 2.0 lbs (0.91 kg)Dimensions: 8.2" H x 4.55" W x 2.3" D (20.82 cm x 11.55 cm x 5.84 cm)