dBu is an absolute measurement. 0dBu is referenced to 0.775 volts RMS
Microphone Pre-Amplifier
Mic to Line (without limiter acting)
Frequency Response: 280 – 15kHz ± 3dB
Microphone output to line – Audio Level (-50dBm Electret input): -9dBm
Microphone output to line – Distortion: <0.1%
Microphone output to line – Signal to Noise: >65dB
Headphone Pre-Amplifier
Frequency Response – Line to Headphone: 150 – 20kHz ± 3dB
Headphone input from line – Audio Level (-9dBm Electret input): 3.5dBm
Headphone input from line – Distortion: <0.5%
Headphone input from line – Signal to Noise: >50dB
Earphone to Mic – Crosstalk: >80dB
Sidetone – Adjustment Range (-80db mic input): >45dB
Keypad Indicators
Power: Green LED
Talk: Green LED
Call: Orange LED
Connectors
Intercom Line: (2) 3-pin XLR–M–F
Pin 1: Common
Pin 2: PL Power (+28V DC)
Pin 3: Line (Audio)