GE Security (IFS) AR7420 4 Channel Digital Audio Receiver. Power supply not included.

From the manufacturer:

 

Features

• 20 Hz – 18kHz Bandwidth
• 600 Ohms Audio Input Impedance
• No In-field Electrical or Optical Adjustments Required
• LED 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 KHz
• Total Harmonic Distortion 0.05%
• Signal-to-Noise Ratio 80 dB (min.)
• Number of Fibers 1
• Current Protection Automatic Resettable Solid-State Current Limiters
• Circuit Board Meets IPC Standard
• MTBF 100,000 hours
• Operating Temp -40° C to +74° C
• Storage Temp -40° C to +85° C
• Relative Humidity 0% to 95% (non-condensing)