Check the listing for details. GE Security (IFS) AR7420 4 Channel Digital Audio Receiver. Condition: Used. Listed at 149.00 USD. GE Security (IFS) AR7420 4 Channel Digital Audio Receiver. Power supply not included. From the manufacturer: Features20 Hz – 18kHz Bandwidth600 Ohms Audio Input ImpedanceNo In-field Electrical or Optical Adjustments RequiredLED Status Indicators for Monitoring Critical Operating Parameters Specs Input/Output Signal 4 (balanced)Audio Input/Output Signal 4.4 volt pk-pk (+6dBm)Bandwidth 20 Hz - 18 KHzTotal Harmonic Distortion 0.05%Signal-to-Noise Ratio 80 dB (min.)Number of Fibers 1Current Protection Automatic Resettable Solid-State Current LimitersCircuit Board Meets IPC StandardMTBF 100,000 hoursOperating Temp -40° C to +74° CStorage Temp -40° C to +85° CRelative Humidity 0% to 95% (non-condensing) The transmitter can be viewed here: GE Security (IFS) AT7420 4 Channel Digital Audio Transmitter | eBay