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4.4.1 Hardwire Duress Alarms. Also called "holdup alarms," this type of
sensor consists of a mechanical switch normally positioned near the person
who will activate it. Banks and Credit Union tellers and other cashier-type
personnel who handle large amounts of cash and deal with the (military)
public are obvious personnel who may need these devices. Other applications
are central alarm station guards, building and facility alarm station
guards, police desk sergeants, and fixed post watchstanders. Most devices
are designed to be foot-activated and require lifting up rather than
pressing down to preclude accidental activation. Covers also protect
against accidental activation. Many types and configurations are available.
High reliability and simple design will assure ease of use and proper
functioning under crisis conditions. Always consider incorporating these
devices in security system design. Make provisions in the security system
design for their use and upgrade plans for thorough training and detailed
procedures as well for actions required by security personnel.
4.4.2 Radio Frequency Duress Alarms. The present mature state-of-the-art
devices resemble paging beepers. They consist of a device about the size of
a pack of cigarettes and are carried inconspicuously on the belt or in a
pocket. Positive activation of an external switch normally activates this
device. This causes a radio frequency signal to be sent to a control unit
in the local area for further transmission to a central alarm station for
action by security personnel. Some belt-mounted units also incorporate a
tilt switch with a timer that automatically activates the alarm signal if
the bearer is not standing or sitting after a preset period of time. This
unit may initially have a high nuisance alarm rate due to user adaptation.
However, it has been documented and the security system designer should plan
for an initial high nuisance alarm rate with the introduction of any
portable duress system. Fixed duress devices have been in use for a very
long time; user confidence tends to be high from the start. Portable
devices are relatively new; thus, users should expect and plan for some
confidence-building trials. Obvious applications include any roving guard
personnel, key personnel in the chain of command, and other key personnel
who are not at fixed operating posts. The critical design consideration is
range of transmitter to relay station or control unit. A large range safety
margin (50 percent minimum) should be allowed for use in case an abduction
attempt delays immediate activation. Considerations of fixed duress alarm
system applications also apply.
4.4.3 Other Approaches to Duress Notification. The sensors discussed above
may not always provide the required application solutions for the security
system designer. Consider especially that "procedure-oriented" duress
notification approaches require detailed documentation, thorough training,
and frequent changes of codes to preclude compromise. These other
approaches to duress notification are:
13.02-67
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