Specifications

MII#ID-1472E
headset. Such sounds may include voices, machine noise that indicates wear or malfunction and other
audible indications of system performancdmission status.
5.3.4.3 Discriminability.
5.3.4.3.1 Use of different characteristics. When several different audio signals are to be used to
alert an operator to different types of conditions, discriminable difference in intensity or pitch, or use
of beats and harmonics shall bc provided. If absolute discrimination is required, the number of signals
to bc identified shall not exceed four.
5.3.4.3.2 Coding. Where discrimination of warning signais tim each other wiUbe critical to
persomel safety or system performance, audio signals shall be appropriately coded. Alarms thatare
perceptibly different shall correlate with different conditions requiring critically different operator
responses (e.g., maintenance, emergency conditions, and health hazards). Such signals shall be
suff~iently different to
rninimk the operator’s search of visual dispIays.
5.3.4.3.3 Critical simtals. The fimt 0.5 second of an audio signal requiring fasi reaction shall be
disaiminable from the fkt 0.5 second of any other signal that may occur. Famiiiar signals with
established names or associations shall be selected. Speech should be
used whenever feasible.
5.3.4.3.4 Action serene
nt. The identifying or action segment of an audio warning signai shall
speci& the precise emergcney or condition requiring action.
5.3.4.3.5 Differentiation from routine signals. Audio alarms intended to bring the operator’s
attention to a malfunction or failure shall be diffemntked
fhrn routine signals, such as
bdb, buzzers,
and normal operation noises.
5.3.4.3.6 Prohibited types
of sifznak. The following types of signals shall not be used as
warnings where possible confusion might exist bemuse of the operational environment
a. Moduktd or interrupted tones that resembk navigation signals or coded radio transmissions.
b. Steady signals that mcmbk hisses, static, or sporadic radio signals.
c. Trains of impulses that resemble electrical interference, whether regularly or imegularly spaced
in time.
d. Simple warbles which may be confusod with the type made by two carriers when one is
being shifted in frequency (beat-frequency-oscillator efYcct).
e. Scrambled speech cfftcts that maybe confined with cress mdukion
Signale from @aloeal
channels.
f. Signals that resemble random noise, periodic pulses, steady or frequency modulated simple
tones, or any other signals generated by standard countermeasure devices (e.g.,
“bagpipes”).
l?.
Signals similar to random noise generated by air conditioning or any other equipment
5.3.4.4 Compatibility.
5.3.4.4.1 Existing simtals. The meaning of audio warning signals selected for a system should
k
L(IIISISUJmivith t~arning sign;ll mc;min:~ iilr(>ii(i~ rstablisht~d for that fl[nctinn