Unbalanced Intercom Channel:
Output Level: 480 mVrms ±10%
Input Impedance: 200 ohm ±5%
Bridging Impedance: greater than 10,000 ohm Call Signalling:
Send: 12 ±3 VDC
Receive: 4 VDC minimum
HEADPHONE AMPLIFIER:
Voltage Gain:
20 ±3 dB from the line
Maximum Output:
60 mW into 150 ohm
Frequency Response:
200 Hz to 8 kHz with no more than 4 dB deviation
Audible Alert:
1 kHz, at the headset
Total Harmonic Distortion:
Less than 2% at 50 mW from the line
Sidetone:
20 dB minimum range, adjustable
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