Telex Airman 850 Operating Instructions Manual page 5

Design Features (See Figure 1)
Fit and Comfort
An adjustable headband gives the wearer two inches (51mm) of up and down
earphone adjustment per side, while the gimbal mounting improves the
headset's side-to-side comfort.
Boom Microphone
The Airman 850 features a miniature, amplified, noise canceling electret
microphone that provides superior 400 Hz hum rejection. The microphone
is mounted on a flexible gooseneck boom that permits precise microphone
placement. The boom rotates 320° to allow the microphone to be worn on
either side of the head. For best results, the microphone should be placed
as close to the mouth as possible. The microphone includes a replaceable
windscreen to minimize popping, hissing, and breathing sounds when
speaking.
Controls
The Airman 850 contains an On/Off switch to control ANR power and a Hi/
Low switch for controlling receiver volume.
Cordage and Plugs
The microphone cordage is protected inside the boom. A strain relief on the
cord provides maximum durability. Shielded wire throughout the headset
protects against RFI (Radio Frequency Interference) and EMI (Electro
Magnetic Interference).
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