Bogen ANS-500 Ambient Noise Senor Control Unit for sale. Four identical units to choose from. Used, but in good condition. C/w owner's manual. Asking $50 each unit. Below is info from the manufacture...
The Bogen Model ANS-500 Ambient Noise Sensor is designed to electronically adjust the input level of a page announcement in an area of a building where ambient noise levels are continuously changing. It ensures that page announcements are audible even during periods of high noise levels. When the signal is boosted, the frequency response is shaped so that speech articulation is more intelligible in the high noise area. The ANS-500 control module monitors the ambient noise level through the use of ANS-500 microphone modules. Each microphone module includes an adjust-able mounting base for precise positioning.
The control unit is capable of supporting up to four (4) microphones wired in parallel; however, if the sound level increases in one area monitored by a microphone, the resulting page signal will be boosted in all areas supplied by the amplifier. Wire runs between the control unit and microphones consist of two-conductor AWG20, and can reach 2,000 feet with no appreciable loss of signal strength.
* ANS Audio In & Out: 3-point terminal strip and RCA jacks
* Sensing Microphone: 2-point terminal strip
* Power: 2-point terminal strip and power jack (center negative)
* Automatic Level Range Gain: 0dB to 18dB
* System Response Delay Time: Approx. 1 or 2.5 seconds (juniper selected)
* In/Out Audio Impedance: Balanced 600 ohms, unbalanced Hi-Z
* Power Source: 24VDC, 30mA
* Operating Temperature: 0 to 55° C
* Dimensions: 4"d x 1¼h x 5¼w