MIL-PRF-26542/2E
REQUIREMENTS:
Component parts:
Boom:
Dimensions: Dimensions of the boom shall be in accordance with USAF Drawing 67B1854,
for interchangeability with the next-higher-assembly headset-microphone.
Color: Boom shall be the same color as the microphone element.
Finish: Shall be in accordance with MIL-PRF-26542 (see boom finish requirement).
Operation: Shall be in accordance with MIL-PRF-26542 (see boom operating force requirement).
Material: Shall be constructed from a high-strength, corrosion-resistant metal, meeting or
exceeding the environmental and durability requirements of MIL-PRF-26542.
Cable assembly: Shall be in accordance with the specified part in order to provide interface to oxygen
gear, for interchangeability, and for environmental performance. The microphone element shall provide
a complete electrical and mechanical interface with the cable assembly. Cable assemblies per PIN are
listed in table I.
Plug assembly: U-173/U, in accordance with USAF Drawing 57B12662, or electrically and mechanically
compatible part.
Weight: 45 grams, maximum.
Performance:
Sensitivity at ground level: 34.0 dB 40.98 dB (re 1 mV) or 50.4 µV 112.0 µV with a Sound Pressure
Level (SPL) input of 28 dynes/cm² at 1 kHz, when tested with the microphone sound port 0.187 inch ±
0.015 inch (4.75 mm ± 0.38mm) from, and coaxial with, the opening of the artificial voice.
Sensitivity at altitude: Shall be within ± 3 dB of initial ground level sensitivity, when tested at a simulated
25,000 feet.
Frequency response envelope at ground level and at altitude: Shall be as shown on figures 2 and 3,
when tested with the microphone sound port 0.187 inch ± 0.015 inch (4.75 mm ± .38 mm) from, and
coaxial with, the opening of the artificial voice. The response curves generated shall be on the same
scale as shown in figures 2 and 3. The response curve shall not exceed the upper and lower limit
curves of the stationary Frequency Response Envelope, within the frequency ranges identified in the
appropriate chart (see figures 2 and 3).
Impedance: 4.0 ohms to 6.0 ohms.
Resistive load: 5 ohms.
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