MIL-PRF-25670/2C
Immersion (H-143A/AIC only):
The earphone element shall be constructed in a watertight manner,
C
such that there is neither penetration (seepage) of water into the
interior of the part, nor any other degradation in performance after
being subjected to the testing described in MIL-STD-810, method
512.3, "Leakage (immersion)", procedure I.
C
Marking (H-143A/AIC only):
Marking shall be in accordance with MIL-PRF-25670, with the
addition that the part shall have the term "IMMERSIBLE" displayed
on the back cover (location optional), in order to better distinguish
the H-143A/AIC from the identical H-143/AIC.
Intended use:
Earphone elements H-143/AIC and H-143A/AIC are low-impedance, light-weight
transducers used in noise-attenuating communications headsets. The H-143/AIC is a replaceable
component of the headset-microphones used by high-altitude aircrew (flight) and groundcrew
personnel, described in documents such as MIL-PRF-87819(USAF), MIL-H-83511 and MIL-E-
83425(USAF). The H-143A/AIC is a low-altitude, water-proof version of the H-143/AIC. It is used by
the US Army as a component of the headset-microphone kit MK-896A/AIC, which is itself a
component of the flying helmet SPH-4.
TABLE I. Part number designations.
Part or Identifying Number (PIN)
Characteristics
H-143/AIC
High- and low-altitude earphone element.
H-143A/AIC
Low-altitude,
water-immersible
earphone
element.
CONCLUDING MATERIAL
Custodians:
Preparing activity:
Air Force - 85
Air Force - 85
Army - CR
Review activities:
(Project 5965-0244-002)
Air Force - 99
DLA - ES
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