Specifications

MIL-STD- 1472E
5.3.8.4 Headsets. lflisteners wil!woti inhighambtent noiw(85dBA orabve), binaural
rather than monaural headsets shall be provided. Unless operational tequitments dictate otherwise,
binaural headsets shall be wired so that the sound reaches the two ears in opposing phases. Their
attenuation qualities should be capable of reducing the ambient noise level to less than 85 dBA.
Provisions should be incorporated to furnish the same protection to those who wear glasses.
5.3.9 Operator comfort and convenience.
5.3.9.1 Comfort Communication equipment to be worn by an operator (e.g., headphones and
telephone headsets) shall be designed to preclude operator discomfort. Metal parts of the headset shall
not come in contact with the user’s skin.
5.3.9.2 Hands-free omxation. Operator microphones, headphones, and telephone headsets
shall be designed to permit hands-frw operation under normal working conditions.
5.3.9.3 Accessibility of handsets. Where communication requirements necessitate the use of
several telephone handsets, the accessibility of theii standby locations shall be determined by
operational priority, i.e., the most frquent.ly or urgentiy needed handset shall be the most ~ible.
The handsets may also be color coded if they will be visible to operating pmonnel under the working
conditions.
5.3.10 Ope
rating controls for voice communication equimnent.
5.3.10.1 Volume controls. Accessible volume or gain controls shall be provided for each
communication receiving channel (e.g., loudspeakers or headphones) with sufficient electrical power
to drive sound pressure level to at least 100 dB overall when using two earphones, and shall have
pressure operated gain control switches to compensate for altitude in unpressurized compartments.
The minimum setting of the volume control shall be limited to an audible leve~ i.e,, it shall no{be
possible to inadvertently disable the system with the volume control. Power (on-off) and volume
adjustment should not be combined into the same contxd; however, if conditions jqstify their
cornbiiation, a
notiaxtble detent position shall be provided between the OFF position and the lower
end of the continuous range of volume adjustment. When combined power and volume controls are
used, the OFF position shall be labeled.
5.3.10.2 SqueJch control. Where communication channels are to be continuously monitoti
each channei shall be provided with a signal-activated switching device (squelch control) to suppress
channel noise during no-signal periods. A manually operated on-off switch, to deactivate the squelch
when receiving weak signals, shall be provided.
5.3.10.3Foot-oWrated controls. When normal vvmking conditions tiil pemtit the opmtor to
remain seated at the working position and require access to “talk-iisten” or “send-receive” control
switches, orifeonsOk 0pmtionrc@rc9 ehctlsevfb@h hands, kmt-Qpemtd wntr0lsshaUk
prwided. ~titikti~~t ib~ovtifu~~y~tifor
use when the operator may need to move from one position to another.
5.3.11 Sueaker/side tone. The speaker’s verbal input shall be in phase with its reproduction as
heard on the headset. This @e tone 4wU not be filwed or mdificd before it is rcccived in the
headset.
5.3.12 S~ech mtelluzlbdlty.
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53 12,1 General. When information concerning the speech intelligibility of a system is
..-— . .
1,’,.l~.lir~*,\{threr wrommcndcfi methods are ~vailah]e. w]th the appro~riate selection hcin~ dependent
upon the
rcquircmcnls nf the test
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