Power your TekTone Apartment Entry System with the TekTone Apartment Intercom Amplifier. This unit works as a power supply, control unit, and power amplifier designed to operate with 3-wire or 4-wire Apartment Speaker Stations (sold separately). Voice volume and audio tone volume controls are adjustable through the front facing screw terminal. The Amplifier also includes multiple door release operation with three delayed door timing modes: AC, DC, or Maglock, and two call tones: steady or warbling. NOTE: Required for IRx03E or IRx04E TekTone Apartment Intercom Stations (sold separately). SPECS: Manufacturer Part Number: PK543A. Dimensions: 5.5 (H) x 3.125 (W) x 2 (D) inches (140 x 80 x 51 mm). Construction: Flame-retardant (UL 94V-0) plastic. Amplification: Integrated circuit amplifier with frequency response, adjusted for ideal voice quality. Call Tone: Integrated circuit oscillator with steady and warble modes. Door Release: AC, DC or Maglock (12 VDC/24 VDC). Controls: Voice Volume, Tone Volume and dip switches for selectable modes. Connections: Polarized plug-in type. Power Required: 16 VAC, 10 VA. Mounting: Surface mount.