NAVIGATION AND
COMMUNICATION
AIRPLANE
OPERATIONS
MANUAL
2-18-20
Page
6
Code
01
JUNE 28, 2002
OBSERVER JACK PANEL AND COMMUNICATION SWITCH (PTT)
1 - BOOM JACK
− Allows plugging-in the boom microphone.
2 - HEADPHONE JACK
− Allows plugging-in in the headphone.
3 - OBSERVER MICROPHONE SWITCH
HOT POSITION - Allows communication with crew members and
ramp station.
OFF POSITION - Allows only audio reception.
PTT POSITION - Momentary position. When pressed allows VHF
and HF transmissions and speech to
passengers through the passenger address
system. Releasing this button, it returns to the
OFF position and transmissions will be
interrupted, remaining only in audio reception.
4 - HEADSET ANR
− Allows plugging-in in the headphone with the Active Noise
Reduction (ANR) feature. The Sennheiser headset model
HMEC25-CAP is certified for ANR function. A switch in the
headset cord activates or deactivates the active noise reduction
feature. If the noise reduction feature malfunctions the headset
must be used with this feature disabled.
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