TERMS AND DEFINITIONS FOR INTRUSION ALARM SYSTEMS

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP96B01172R000700140003-8
• Release Decision: RIFPUB
• Original Classification: K
• Document Page Count: 22
• Document Creation Date: December 20, 2016
• Document Release Date: May 11, 2007
• Sequence Number: 3
• Publication Date: October 1, 1974
• Content Type: REGULATION

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LESP-RPT-0305.00
OCTOBER 1974
LAW ENFORCEMENT STANDARDS PROGRAM
TERMS AND DEFINITIONS
FOR
INTRUSION ALARM SYSTEMS
U.S. DEPARTMENT OF JUSTICE
Law Enforcement Assistance Administration
National Institute of Law Enforcement and Criminal Justice
 RETENTION
PURCHASE APPROVAL
COST CENTER
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PHONE DATE NEEDED
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LAW ENFORCEMENT STANDARDS PROGRAM
TERMS AND DEFINITIONS
FOR
INTRUSION ALARM SYSTEMS
prepared for
National Institute of Law Enforcement and Criminal Justice
Law Enforcement Assistance Administration
U.S. Department of Justice
by
G. N. Stenbakken
W. E. Phillips
Electronic Technology Division
and
S. E. Bergsman
Technical Analysis Division
National Bureau of Standards
OCTOBER 1974
U.S. DEPARTMENT OF JUSTICE
Law Enforcement Assistance Administration
National Institute of Law Enforcement and Criminal Justice
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LAW ENFORCEMENT ASSISTANCE
ADMINISTRATION
Richard W. Velde, Administrator
Charles R. Work, Deputy Administrator
NATIONAL INSTITUTE OF LAW ENFORCEMENT
AND CRIMINAL JUSTICE
Gerald M. Caplan, Director
This document was prepared by the Law Enforcement Standards Laboratory of
the National Bureau of Standards under the direction of Marshall A.Isler and
Lawrence K. Eliason, Managers, Security Systems Program, and Jacob J.
Diamond, Chief of LESL. Many of the definitions are based on those contained
in glossaries published by Mosler Electronic Systems, Honeywell, American
District Telegraph Company, American National Standards Institute, Institute of
Electrical and Electronics Engineers, National Electrical Manufacturers Associ-
ation, National Fire Protection Association, and Underwriters Laboratories, Inc.
For sale by the Superintendent of Documents, U.S. Government Printing Office
Washington, D.C. 20402 - Price: 65 cents
Stock Number 027-000-00290-1
Catalog Number J 1.41 :0305.00
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FOREWORD
Following a Congressional mandate* to develop new and improved
techniques, systems, and equipment to strengthen law enforcement and
criminal justice, the National Institute of Law Enforcement and Criminal
Justice (NILECJ) has established the Law Enforcement Standards Laboratory
(LESL) at the National Bureau of Standards. LESL's function is to conduct
research that. will assist law enforcement and criminal justice agencies in the
selection and procurement of quality equipment.
In response to priorities established. by NILECJ, LESL is (1) subjecting
existing equipment to laboratory testing and evaluation and (2) conducting
research leading to the development of several series of documents, including
national voluntary equipment standards, user guidelines, state-of-the-art sur-
veys and other reports.
This document, LESP-RPT-0305.00, Terms and Definitions for Intru-
sion Alarm Systems, is a law enforcement equipment report prepared by LESL
and issued by NILECJ. Additional reports as well as other documents will be
issued under the LESL program in the areas of protective equipment, commu-
nications equipment, security systems, weapons, emergency equipment, in-
vestigative aids, vehicles and clothing.
Technical comments and suggestions concerning the subject matter of
this report are invited from all interested parties. Comments should be
addressed to the Manager, Standards Program, National Institute of Law
Enforcement and Criminal Justice, Law Enforcement Assistance Administra-
tion, U.S. Department of Justice, Washington, D.C. 20531.
Lester D. Shubin
Manager, Standards Program
National Institute of Law
Enforcement and Criminal Justice
* Section 402(b) of the Omnibus Crime Control and Safe Streets Act of 1968,
as amended.
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TERMS AND DEFINITIONS
ACCESS CONTROL.-The control of pedes-
trian and vehicular traffic through entrances and
exits of a PROTECTED AREA or premises.
ACCESS MODE.-The operation of an
ALARM SYSTEM such that no ALARM
SIGNAL is given when the PROTECTED AREA
is entered; however, a signal may be given if the
SENSOR, ANNUNCIATOR, or CONTROL
UNIT is tampered with or opened.
ACCESS/SECURE CONTROL UNIT.-See
CONTROL UNIT.
ACCESS SWITCH.-See AUTHORIZED
ACCESS SWITCH.
ACCUMULATOR.-A circuit which accu-
mulates a sum. For example, in an audio alarm
control unit, the accumulator sums the ampli-
tudes of a series of pulses, which are larger than
some threshold level, subtracts from the sum at a
predetermined rate to account for random back-
ground pulses, and initiates an alarm signal when
the sum exceeds some predetermined level. This
circuit is also called an integrator; in digital
circuits it may be called a counter.
ACTIVE INTRUSION SENSOR.-An active
sensor which detects the presence of an intruder
within the range of the sensor. Examples are an
ULTRASONIC MOTION DETECTOR, a RA-
DIO FREQUENCY MOTION DETECTOR,
and a PHOTOELECTRIC ALARM SYSTEM.
See also PASSIVE INTRUSION SENSOR.
ACTIVE SENSOR.-A sensor which detects
the disturbance of a radiation field which is gen-
erated by the sensor. See also PASSIVE SENSOR.
ACTUATING DEVICE.-See ACTUATOR.
ACTUATOR.-A manual or automatic
switch or sensor such as HOLDUP BUTTON,
MAGNETIC SWITCH, or thermostat which
causes a system to transmit an ALARM SIGNAL
when manually activated or when the device au-
tomatically senses an intruder or other unwanted
condition.
AIR GAP.-The distance between two mag-
netic elements in a magnetic or electromagnetic
circuit, such as between the core and the arma-
ture of a relay.
ALARM.-An ALARM DEVICE or an
ALARM SIGNAL.
ALARM CIRCUIT.-An electrical circuit of
an alarm system which produces or transmits an
ALARM SIGNAL.
ALARM CONDITION.-A threatening con-
dition, such as an intrusion, fire, or holdup,
sensed by a DETECTOR.
ALARM DEVICE.-A device which signals a
warning in response to a ALARM CONDITION,
such as a bell, siren, or ANNUNCIATOR.
ALARM DISCRIMINATION.-The ability
of an alarm system to distinguish between those
stimuli caused by an INTRUSION and those
which are a part of the environment.
ALARM LINE.-A wired electrical circuit
used for the transmission of ALARM SIGNALS
from the protected premises to a MONITORING
STATION.
ALARM RECEIVER.-See ANNUNCIA-
TOR.
ALARM SENSOR.-See SENSOR.
ALARM SIGNAL.-A signal produced by a
CONTROL UNIT indicating the existence of
an'ALARM CONDITION.
ALARM STATE.-The condition of a DE-
TECTOR which causes a CONTROL UNIT in
the SECURE MODE to transmit an ALARM
SIGNAL.
ALARM STATION.-(1) A manually actu-
ated device installed at a fixed location to transmit
an ALARM SIGNAL in response to an ALARM
CONDITION, such as a concealed HOLDUP
BUTTON in a bank teller's cage. (2) A well-
marked emergency control unit, installed in fixed
locations usually accessible to the public, used to
summon help in response to an ALARM CON-
DITION. The CONTROL UNIT contains either
a manually actuated switch or telephone con-
nected to fire or police headquarters, or a tele-
phone answering service. See also REMOTE
STATION ALARM SYSTEM.
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ALARM SYSTEM.-An assembly of equip- amplifiers and speakers designed to monitor the
ment and devices designated and arranged to
signal the presence of an ALARM CONDITION
requiring urgent attention such as unauthorized
entry, fire, temperature rise, etc. The system may
be LOCAL, POLICE CONNECTION, CEN-
TRAL STATION or PROPRIETARY. (For indi-
vidual alarm systems see alphabetical listing by
type, e.g., INTRUSION ALARM SYSTEM.)
ANNUNCIATOR.-An
device which consists of a
alarm monitoring
number of visible
signals such as "flags" or lamps indicating the
status of the DETECTORS in an alarm system or
systems. Each circuit in the device is usually
labelled to identify the location and condition
being monitored. In addition to the visible sig-
nal, an audible signal is usually associated with
the device. When an alarm condition is reported,
a signal is indicated visibly, audibly, or both.
The visible signal is generally maintained until
reset either manually or automatically.
ANSWERING SERVICE.-A business which
contracts with subscribers to answer incoming
telephone calls after a specified delay, or when
scheduled to do so. It may also provide other
services such as relaying fire or intrusion alarm
signals to proper authorities.
AREA PROTECTION.-Protection of the
inner space or volume of a secured area by means
of a VOLUMETRIC SENSOR.
AREA SENSOR.-A sensor with a detection
zone which approximates an area, such as a wall
surface or the exterior of a safe.
AUDIBLE ALARM DEVICE.-(1) A noise-
making device such as a siren, bell, or horn used
as part of a local alarm system to indicate an
ALARM CONDITION. (2) A bell, buzzer, horn
or other noisemaking device used as a part of an
ANNUNCIATOR to indicate a change in the
status or operating mode of an alarm system.
AUDIO DETECTION SYSTEM.-See
SOUND SENSING DETECTION SYSTEM.
AUDIO FREQUENCY (SONIC).-Sound
frequencies within the range of human hearing,
approximately 15 to 20,000 Hz.
AUDIO MONITOR.-An arrangement
sounds transmitted by microphones located in the
PROTECTED AREA. Similar to an ANNUN-
CIATOR, except that supervisory personnel can
monitor the , protected. area to interpret the
sounds.
AUTHORIZED ACCESS SWITCH.-A de-
vice used to make an alarm system or some
portion or zone of a system inoperative in order to
permit authorized access through a PRO-
TECTED PORT. A SHUNT is an example of
such a device.
B. A.-Burglar alarm.
BEAM DIVERGENCE. -In
ELECTRIC ALARM SYSTEM,
spread of the light beam.
a PHOTO-
the angular
. BREAK ALARM.-(1) An ALARM CONDI-
TION signaled by the opening or breaking of an
electrical circuit. (2) The signal produced by a
break alarm condition (sometimes referred to as
an open circuit alarm or trouble signal, designed
to indicate possible system failure).
BUG.-(1) To plant a microphone or other
SOUND SENSOR or to tap a communication
line for the purpose of SURREPTITIOUS listen-
ing or AUDIO MONITORING; loosely, to in-
stall a sensor in a specified location. (2) The
microphone or other sensor used for the purpose
of surreptitious listening.
BUILDING SECURITY ALARM SYS-
TEM.-The system of PROTECTIVE SIGNAL-
ING devices installed at a premise.
BURGLAR ALARM (B. A.) PAD.-A sup-
porting frame laced with fine wire or a fragile
panel located with FOIL or'fine wire and installed
so as to cover an exterior opening in a building,
such as a door, or skylight. Entrance through the
opening breaks the wire or foil and initiates an
ALARM SIGNAL. See also GRID.
BURGLAR ALARM SYSTEM.-See IN-
TRUSION ALARM SYSTEM.
BURGLARY.-The unlawful entering of a
structure with the intent to commit a felony or
theft therein.
CABINET-FOR-SAFE .-A wooden enclosure
having closely spaced electrical GRIDS on all
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inner surfaces and CONTACTS on the doors. It such as by jumping over a pressure sensitive
surrounds a safe and initiates an alarm signal if an
attempt is made to open or penetrate the cabinet.
CAPACITANCE.-The property of two or
more objects which enables them to store electri-
cal energy in an electric field between them. The
basic measurement unit is the farad. Capacitance
varies inversely with the distance between the
objects, hence the change of capacitance with
relative motion is greater the nearer one object is
to the other.
CAPACITANCE ALARM SYSTEM.-An
alarm system in which a protected object is elec-
trically connected as a CAPACITANCE SEN-
SOR. The approach of an intruder causes suffi-
cient change in CAPACITANCE to upset the
balance of the system and initiate an ALARM
SIGNAL. Also called proximity alarm system.
CAPACITANCE DETECTOR.-See CA-
PACITANCE SENSOR.
CAPACITANCE SENSOR.-A sensor which
responds to a change in CAPACITANCE in a
field containing a protected object or in a field
within a protected area.
CARRIER CURRENT TRANSMITTER.-A
device which transmits ALARM SIGNALS from
a sensor to a CONTROL UNIT via the standard
ac power lines.
CENTRAL STATION.-A control center to
which alarm systems in a subscriber's premises
are connected, where circuits are supervised, and
where personnel are maintained continuously to
record and investigate alarm or trouble signals.
Facilities are provided for the reporting of alarms
to police and fire departments or to other outside
agencies.
CENTRAL STATION ALARM SYSTEM.-
An alarm system, or group of systems, the activi-
ties of which are transmitted to, recorded in,
maintained by, and supervised from a CENTRAL
STATION. This differs from PROPRIETARY
ALARM SYSTEMS in that the central station is
owned and operated independently of the subscri-
ber.
CIRCUMVENTION.-The defeat of an alarm
system by the avoidance of its detection devices,
mat, by entering through a hole cut in an
unprotected wall rather than through a protected
door, or by keeping outside the range of an
ULTRASONIC MOTION DETECTOR.
Circumvention contrasts with SPOOFING.
CLOSED CIRCUIT ALARM.-See CROSS
ALARM.
CLOSED CIRCUIT SYSTEM.-A system in
which the sensors of each zone are connected in
series so that the same current exists in each
sensor. When an activated sensor breaks the cir-
cuit or the connecting wire is cut, an alarm is
transmitted for that zone.
CLUTCH HEAD SCREW.-A mounting
screw with a uniquely designed head for which
the installation and removal tool is not commonly
available. They are used to install alarm system
components so that removal is inhibited.
CODED-ALARM SYSTEM.-An alarm sys-
tem in which the source of each signal is identifi-
able. This is usually accomplished by means of a
series of current pulses which operate audible or
visible ANNUNCIATORS or recorders or both,
to yield a recognizable signal. This is usually used
to allow the transmission of multiple signals on a
common circuit.
CODED CABLE.-A multiconductor cable in
which the insulation on each conductor is distin-
guishable from all others by color or design. This
assists in identification of the point of origin or
final destination of a wire.
CODED TRANSMITTER.-A device for
transmitting a coded signal when manually or
automatically operated by an ACTUATOR. The
actuator may be housed with the transmitter or a
number of actuators' may operate a common
transmitter.
CODING SIREN.-A siren which has an aux-
iliary mechanism to interrupt the flow of air
through its principal mechanism, enabling it to
produce a controllable series of sharp blasts.
COMBINATION SENSOR ALARM SYS-
TEM.-An alarm system which requires the si-
multaneous activation of two or more sensors to
initiate an ALARM SIGNAL.
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COMPROMISE.-See DEFEAT.
CONSTANT RINGING DROP (CRD).-A
relay which when activated even momentarily
will. remain in an ALARM CONDITION until
RESET. A key is often required to reset the relay
and turn off the alarm.
CONSTANT RINGING RELAY (CRR).-
See CONSTANT RINGING DROP.
CONTACT.-(1) Each of the pair of metallic
parts of a switch or relay which by touching or
separating make or break the electrical current
path. (2) A switch-type sensor.
CONTACT DEVICE.-A device which when
actuated opens or closes a set of electrical con-
tacts; a switch or relay.
CONTACT MICROPHONE.-A micro-
phone designed for attachment directly to a sur-
face of a PROTECTED AREA or object; usually
used to detect surface vibrations.
CONTACT VIBRATION SENSOR.-See
VIBRATION SENSOR.
CONTACTLESS VIBRATING BELL.-A
VIBRATING BELL whose continuous operation
depends upon application of an alternating cur-
rent, without circuit-interrupting contacts such
as those used in vibrating bells operated by direct
current.
CONTROL CABINET.-See CONTROL
UNIT.
CONTROL UNIT.-A device, usually ELEC-
TRONIC, which provides the interface between
the alarm system and the human operator and
produces an ALARM SIGNAL when its pro-
grammed response indicates an ALARM CON-
DITION. Some or all of the following may be
provided for: power for sensors, sensitivity ad-
justments, means to select and indicate ACCESS
MODE or SECURE MODE, monitoring for
LINE SUPERVISION and TAMPER DEVICES,
timing circuits, for ENTRANCE and EXIT DE-
LAYS, transmission of an alarm signal, etc.
COVERT.-Hidden and protected.
CRD.-See CONSTANT RINGING DROP.
CROSS ALARM.-(1) An ALARM CONDI-
TION signaled by crossing or shorting an electri-
cal circuit. (2) The signal produced due to a cross
alarm condition.
CROSSOVER.-An insulated electrical path
used to connect foil across window dividers, such
as those found on multiple pane windows, to
prevent grounding and to make a more durable
connection.
CRR.-Constant ringing relay. See CON-
STANT RINGING DROP.
DARK CURRENT.-The current output of a
PHOTOELECTRIC SENSOR when no light is
entering the sensor.
DAY SETTING.-See ACCESS MODE.
DEFEAT.-The frustration, counteraction, or
thwarting of an ALARM DEVICE so that it fails
to signal an alarm when a protected area is en-
tered. Defeat includes both CIRCUMVENTION
and SPOOFING.
DETECTION RANGE.-The greatest dis-
tance at which a sensor will consistently detect an
intruder under a standard set of conditions.
DETECTOR.-(1) A sensor such as those used
to detect INTRUSION, equipment malfunctions
or failure, rate of temperature rise, smoke or fire.
(2) A demodulator, a device for recovering the
modulating function or signal from a modulated
wave, such as that used in a modulated photo-
electric alarm system. See also PHOTOELEC-
TRIC ALARM SYSTEM, MODULATED.
DIALER.-See TELEPHONE DIALER, AU-
TOMATIC.
DIFFERENTIAL PRESSURE SENSOR.-A
sensor used for PERIMETER PROTECTION
which responds to the difference between the
hydraulic pressures in two liquid-filled tubes
buried just below the surface of the earth around
the exterior perimeter of the PROTECTED
AREA. The pressure difference can indicate an
intruder walking or driving over the buried
tubes.
DIGITAL TELEPHONE DIALER.-See
TELEPHONE DIALER, DIGITAL.
DIRECT CONNECT.-See POLICE CON-
NECTION.
DIRECT WIRE BURGLAR ALARM CIR-
CUIT (DWBA).-See ALARM LINE.
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DIRECT WIRE CIRCUIT.-See ALARM
LINE.
DOOR CORD.-A short, insulated cable
with an attaching block and terminals at each end
used to conduct current to a device, such as
FOIL, mounted on the movable portion of a door
or window.
DOOR TRIP SWITCH.-A MECHANICAL
SWITCH mounted so that movement of the door
will operate the switch.
DOPPLER EFFECT (SHIFT).-The apparent
change in frequency of sound or radio waves when
reflected from or originating from a moving ob-
ject. Utilized in some types of MOTION SEN-
SORS.
DOUBLE-CIRCUIT SYSTEM.-An ALARM
CIRCUIT in which two wires enter and two wires
leave each sensor.
DOUBLE DROP.-An alarm signaling
method often used in CENTRAL STATION
ALARM SYSTEMS in which the line is first
opened to produce a BREAK ALARM and then
shorted to produce a CROSS ALARM.
DROP.-(1) See ANNUNCIATOR. (2) A
light indicator on an annunciator.
DURESS ALARM DEVICE.-A device which
produces either a SILENT ALARM or LOCAL
ALARM under a condition of personnel stress
such as holdup, fire, illness, or other panic or
emergency. The device is normally manually op-
erated and may be fixed or portable.
DURESS ALARM SYSTEM.-An alarm sys-
tem which employes a DURESS ALARM DE-
VICE.
DWBA.-Direct wire burglar alarm. See
ALARM LINE.
E-FIELD SENSOR.-A PASSIVE SENSOR
which detects changes in the earth's ambient
electric field caused by the movement of an in-
truder. See also H-FIELD SENSOR.
ELECTRICAL.-Related to,.pertaining to, or
associated with electricity.
ELECTROMAGNETIC.-Pertaining to the
relationship between current flow and magnetic
field.
ELECTROMAGNETIC INTERFERENCE
(EMI).-Impairment of the reception of a wanted
electromagnetic signal by an electromagnetic dis-
turbance. This can be caused by lightning, radio
transmitters, power line noise and other electrical
devices.
ELECTROMECHANICAL BELL.-A bell
with a prewound spring-driven striking mecha-
nism, the operation of which is initiated by the
activation of an electric tripping mechanism.
ELECTRONIC.-Related to,, or pertaining
to, devices which utilize electrons moving
through a vacuum, gas, or semiconductor, and to
circuits or systems containing such devices.
EMI.-See ELECTROMAGNETIC INTER-
FERENCE.
END OF LINE RESISTOR.-See TERMI-
NAL RESISTOR.
ENTRANCE DELAY.-The time between
actuating a sensor on an entrance door or gate and
the sounding of a LOCAL ALARM or transmis-
sion of an ALARM SIGNAL by the CONTROL
UNIT. This delay is used if the AUTHORIZED
ACCESS SWITCH is located within the PRO-
TECTED AREA and permits a person with the
control key to enter without causing an alarm.
The delay is provided by a timer within the
CONTROL UNIT.
E.O.L.-End of line.
EXIT DELAY.-The time between turning
on a control unit and the sounding of a LOCAL
ALARM or transmission of an ALARM SIGNAL
upon actuation of a sensor on an exit door. This
delay is used if the AUTHORIZED ACCESS
SWITCH is located within the PROTECTED
AREA and permits a person with the control key
to turn on the alarm system and to leave through
a protected door or gate without causing an
alarm. The delay is provided by a timer within
the CONTROL UNIT.
FAIL SAFE.-A feature of a system or device
which initiates an alarm or trouble signal when
the system or device either malfunctions or loses
power.
FALSE ALARM.-An alarm signal transmit-
ted in the absence of an ALARM CONDITION.
These may be classified according to causes: envi-
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ronmental, e.g., rain, fog, wind, hail, lightning, TEM which employs a CONTACT MICRO-
temperature, etc.; animals, e.g., rats, dogs, cats,
insects, etc.; man-made disturbances, e.g., sonic
booms, EMI, vehicles, etc.; equipment malfunc-
tion, e.g., transmission errors, component fail-
ure, etc.; operator error; and unknown.
FALSE ALARM RATE, MONTHLY.-The
number of false alarms -per installation per
month.
FALSE ALARM RATIO.-The ratio of
FALSE ALARMS to total alarms; may be ex-
pressed as a percentage or as a simple ratio.
FENCE ALARM.-Any of several types of
sensors used to detect the presence of an intruder
near a fence or any attempt by him to climb over,
go under, or cut through the fence.
FIELD.-The space or area in which there
exists a force such as that produced by an electri-
cally charged object, a current, or a magnet.
FIRE DETECTOR (SENSOR).-See HEAT
SENSOR and SMOKE DETECTOR.
FLOOR MAT.-See MAT SWITCH.
FLOOR TRAP.-A TRAP installed so as to
detect the movement of a person across a floor
space, such as a TRIP WIRE SWITCH or MAT
SWITCH.
FOIL.-Thin metallic strips which are ce-
mented to a protected surface (usually glass in a
window or door), and connected to a closed elec-
trical circuit. If the protected material is broken
so as to break the foil, the circuit opens, initiat-
ing an alarm signal. Also called tape. A window,
door, or other surface to which foil has been
applied is said to be taped or foiled.
FOIL CONNECTOR.-An electrical terminal
block used on the edge of a window to join
interconnecting wire to window FOIL.
FOOT RAIL.-A HOLDUP ALARM DE-
VICE, often used at cashiers' windows, in which
a foot is placed under the rail, lifting it, to
initiate an ALARM SIGNAL.
FREQUENCY DIVISION MULTIPLEXING
(FDM).-See MULTIPLEXING, FREQUENCY
DIVISION.
GLASSBREAK ? VIBRATION DETEC-
TOR.-A VIBRATION DETECTION SYS-
PHONE attached to a glass window to detect
cutting or breakage of the glass.
GRID.-(1) An arrangement of electrically
conducting wire, screen, or tubing placed in
front of doors or windows or both which is used as
a part of a CAPACITANCE SENSOR. '(2) a
lattice of wooden dowels or slats c::ncealing fine
wires in a closed circuit which initiates an
ALARM SIGNAL when forcing or cutting the
lattice breaks the wires. Used over accessible
openings. Sometimes called a protective screen.
See also BURGLAR ALARM PAD. (3) A screen
or metal plate, connected to earth ground, some-
times used to provide a stable ground reference
for objects protected by a CAPACITANCE SEN-
SOR. If placed against the walls near the pro-
tected object, it prevents the sensor sensitivity
from extending through the walls into areas of
activity.
HEAT DETECTOR.-See HEAT SENSOR.
HEAT SENSOR.-(1) A sensor which re-
sponds to either a local temperature above a
selected value, a local temperature increase which
is at a rate of increase greater than a preselected
rate (rate of rise), or both. (2) A sensor which
responds to infrared radiation from a remote
source such as a person.
H-FIELD SENSOR.-A PASSIVE SENSOR
which detects changes in the earth's ambient
magnetic field caused by the movement of an
intruder. See also E-FIELD SENSOR.
HOLDUP.-A ROBBERY involving the
threat to use a weapon.
HOLDUP ALARM DEVICE.-A device
which signals a holdup. The device is usually
SURREPTITIOUS and may be manually or auto-
matically actuated, fixed or portable. See DU-
RESS ALARM DEVICE.
HOLDUP ALARM SYSTEM, AUTO-
MATIC.-An alarm system which employs a
holdup alarm device, in which the signal trans-
mission is initiated solely by the action of the
intruder, such as a money clip in a cash drawer.
HOLDUP ALARM SYSTEM, MANUAL.-
A holdup alarm system.in which the signal trans-
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mission is initiated by the direct action of the
person attacked or of an observer of the attack.
HOLDUP BUTTON.-A manually actuated
MECHANICAL SWITCH used to initiate a du-
ress alarm signal; usually constructed to mini-
mize accidental activation.
. HOOD CONTACT.-A switch which is used
for the supervision of a closed safe or vault door.
Usually installed on the outside surface of the
protected door.
IMPEDANCE.-The opposition to the flow -of
alternating current in a circuit. May be deter-
mined by the ratio of an input voltage to the
resultant current.
IMPEDANCE MATCHING.-Making the
IMPEDANCE of a TERMINATING DEVICE
equal to the impedance of the circuit to which it
is connected in order to achieve optimum signal
transfer.
INFRARED (IR) MOTION DETECTOR.-
A sensor which detects changes in the infrared
light radiation from parts of the PROTECTED
AREA. Presence of an intruder in the area
changes the infrared light intensity from his di-
rection.
INFRARED (IR) MOTION SENSOR.-See
INFRARED MOTION DETECTOR.
INFRARED SENSOR.-See HEAT SEN-
SOR, INFRARED MOTION DETECTOR, and
PHOTOELECTRIC SENSOR.
INKING REGISTER.-See REGISTER,
INKING.
INTERIOR PERIMETER PROTECTION.-
A line of protection along the interior boundary
of a PROTECTED AREA including all points
through which entry can be effected.
INTRUSION. -Unauthorized entry into the
property of another.
INTRUSION ALARM SYSTEM.-An alarm
system for signaling the entry or attempted entry
of a person or an object into the area or volume
protected by the system.
IONIZATION SMOKE DETECTOR.-A
SMOKE DETECTOR in which a small amount
of radioactive material ionizes the air in the sen-
sing chamber, thus rendering it conductive and
permitting a current to flow through the air
between two charged electrodes. This effectively
gives the sensing chamber an electrical conduct-
ance. When smoke particles enter the ionization
area, they decrease the conductance of the air by
attaching themselves to the ions causing a reduc-
tion in mobility. When the conductance is less
than a predetermined level, the detector circuit
responds.
IR.-Infrared.
JACK.-An electrical connector which is used
for frequent connect and disconnect operations;
for example, to connect an alarm circuit at an
overhang door.
LACING.-A network of fine wire surround-
ing or covering an area to be protected, such as a
safe, vault, or glass panel, and connected into a
CLOSED CIRCUIT SYSTEM. The network of
wire is concealed by a shield such as concrete or
paneling in such a manner that an attempt to
break through the shield breaks the wire and
initiates an alarm.
LIGHT INTENSITY CUTOFF.-In a PHO-
TOELECTRIC ALARM SYSTEM, the percent
reduction of light which initiates an ALARM
SIGNAL at the photoelectric receiver unit.
LINE AMPLIFIER.-An audio amplifier
which is used to provide preamplification of an
audio ALARM SIGNAL before transmission of
the signal over an ALARM LINE. Use of an
amplifier extends the range of signal transmis-
sion.
LINE SENSOR (DETECTOR).-A sensor
with a detection zone which approximates a line
or series of lines, such as a PHOTOELECTRIC
SENSOR, which senses a direct or reflected light
beam.
LINE SUPERVISION.-Electronic protection
of an ALARM LINE accomplished by sending a
continuous or coded signal through the circuit. A
change in the circuit characteristics, such as a
change in IMPEDANCE due to the circuit's hav-
ing been tampered with, will be detected by a
monitor. The monitor initiates an alarm if the
change exceeds a predetermined amount.
LOCAL ALARM.-An alarm which when ac-
 Approved For Release 2007/05/11
tivated makes a loud noise (see AUDIBLE
ALARM DEVICE) at or near the PROTECTED
AREA or floods the site with light or both.
LOCAL ALARM SYSTEM.-An alarm sys-
tem which when activated produces an audible or
visible signal in the immediate vicinity of the
protected premises or object. This term usually
applies to systems designed to provide only a
? local warning of INTRUSION and not to trans-
mit to a remote MONITORING STATION.
However, local alarm systems are sometimes used
in conjunction with a REMOTE ALARM.
LOOP.-An electric circuit consisting of.sev-
eral elements, usually switches, connected in se-
ries.
MAGNETIC ALARM SYSTEM.-An alarm
system which will initiate an alarm when it de-
tects changes in the local magnetic field. The
changes could be caused by motion of ferrous
objects such as guns or tools near the MAG-
NETIC SENSOR.
MAGNETIC CONTACT.-See MAGNETIC
SWITCH.
MAGNETIC SENSOR.-A sensor which re-
sponds to changes in magnetic field. See also
MAGNETIC ALARM SYSTEM.
MAGNETIC SWITCH.-A switch which
consists of two separate units: a magnetically-
actuated switch, and a magnet. The switch is
usually mounted in a fixed position (door jamb or
window frame) opposing the magnet, which is
fastened to a hinged or sliding door, window,
etc. When the movable section is opened, the
magnet moves with it, actuating the switch.
MAGNETIC SWITCH, BALANCED.-A
MAGNETIC SWITCH which operates using a
balanced magnetic field in such a manner as to
resist DEFEAT with an external magnet, It sig-
nals an alarm when it detects either an increase or
decrease in magnetic field strength.
MATCHING NETWORK.-A circuit used
to achieve IMPEDANCE MATCHING. It may
also allow audio signals to be transmitted to an
ALARM LINE while blocking direct current
used locally for LINE SUPERVISION.
MAT SWITCH.-A flat area switch used on
CIA-RDP96B01172R000700140003-8
open floors or under carpeting. It may be sensi-
tive over an area of a. few square feet or several
square yards.
McCULLOH CIRCUIT (LOOP).-A super-
vised single wire LOOP connecting a number of
CODED TRANSMITTERS located in different
PROTECTED AREAS to a CENTRAL STA-
TION receiver.
MECHANICAL SWITCH.-A switch in
which the CONTACTS are opened and closed by
means of a depressible plunger or button.
MERCURY FENCE ALARM.-A type of
MERCURY SWITCH which is sensitive to the
vibration caused by an intruder climbing on a
fence.
MERCURY SWITCH.-A switch operated
by tilting or vibrating which causes an enclosed
pool of mercury to move, making or breaking
physical and. electrical contact with conductors.
These are used on tilting doors and windows, and
on fences.
MICROWAVE ALARM SYSTEM.-An
alarm system which employs RADIO FRE-
QUENCY MOTION DETECTORS operating in
the MICROWAVE FREQUENCY region of the
electromagnetic spectrum.
MICROWAVE FREQUENCY.-Radio fre-
quencies in the range of approximately 1.0 to 300
GHz.
MICROWAVE MOTION DETECTOR.-
See RADIO FREQUENCY MOTION DETEC-
TOR.
MODULATED PHOTOELECTRIC ALARM
SYSTEM.-See PHOTOELECTRIC ALARM
SYSTEM, MODULATED.
MONITOR CABINET.-An enclosure which
houses the ANNUNCIATOR and associated
equipment.
MONITOR PANEL.-See ANNUNCIA-
TOR.
MONITORING STATION.-The CEN-
TRAL STATION or other area at which guards,
police, or commercial service personnel observe
ANNUNCIATORS and REGISTERS reporting
on the condition of alarm, systems.
 Approved For Release 2007/05/11 :
MOTION DETECTION SYSTEM.-See
MOTION SENSOR.
MOTION DETECTOR.-See MOTION
SENSOR.
MOTION SENSOR.-A sensor which re-
sponds to the motion of an intruder. See also
RADIO FREQUENCY MOTION DETECTOR,
SONIC MOTION DETECTOR, ULTRASONIC
MOTION DETECTOR, AND INFRARED
MOTION DETECTOR.
MULTIPLEXING.-A technique for the con-
current transmission of two or more signals in
either or both directions, over the same wire,
carrier, or other communication channel. The
two basic multiplexing techniques are time divi-
sion multiplexing and frequency division multi-
plexing.
MULTIPLEXING, FREQUENCY DIVI-
SION (FDM).-The multiplexing technique
which assigns to each signal a specific set of
frequencies (called a channel) within the larger
block of frequencies available on the main trans-
mission path in much the same way that many
radio stations broadcast at the same time but can
be separately received.
MULTIPLEXING, TIME 'DIVISION
(TDM).-The multiplexing technique which
provides for the independent transmission of sev-
eral pieces of information on a time-sharing basis
by sampling, at frequent intervals, the data to be
transmitted.
NEUTRALIZATION.-See DEFEAT.
NICAD.-(Contraction of "nickel cad-
mium".) A high performance, long-lasting re-
chargeable battery, with electrodes made of
nickel and cadmium, which may be used as an
emergency power supply for an alarm system.
NIGHT SETTING.-See SECURE MODE.
NONRETRACTABLE (ONE-WAY)
SCREW.-A screw with a head designed to per-
mit installation with an ordinary flat bit screw-
driver but which resists removal. They are used to
install alarm system components so that removal
is inhibited.
NORMALLY CLOSED (NC) SWITCH.-A
CIA- R D P 96 B 011 72 R 000700140003-8
switch in which the CONTACTS are closed when
no external forces act upon the switch.
NORMALLY OPEN (NO) SWITCH.-A
switch in which the CONTACTS are open (sepa-
rated) when no external forces act upon the
switch.
NUISANCE ALARM.-See FALSE ALARM.
OBJECT PROTECTION.-See SPOT PRO-
TECTION.
OPEN-CIRCUIT ALARM.-See BREAK
ALARM.
OPEN-CIRCUIT SYSTEM.-a system in
which the sensors are connected in parallel.
When a sensor is activated, the circuit is closed,
permitting a current which activates an ALARM
SIGNAL.
PANIC ALARM.-See DURESS ALARM
DEVICE.
PANIC BUTTON.-See DURESS ALARM
DEVICE.
PASSIVE INTRUSION SENSOR.-A passive
sensor in an - INTRUSION ALARM SYSTEM
which detects an intruder within the range of the
sensor. Examples are a SOUND SENSING DE-
TECTION SYSTEM, a VIBRATION DETEC-
TION SYSTEM, an INFRARED MOTION DE-
TECTOR, and an E-FIELD SENSOR.
PASSIVE SENSOR.-A sensor which detects
natural radiation or radiation disturbances, but
does not itself emit the radiation on which its
operation depends.
PASSIVE ULTRASONIC ALARM SYS-
TEM.-An alarm system which detects the
sounds in the ULTRASONIC FREQUENCY
range caused by an attempted forcible entry into a
protected structure. The system consists of mi-
crophones, a CONTROL UNIT containing an
amplifier, filters, an ACCUMULATOR, and a
power supply. The unit's sensitivity is adjustable
so that ambient noises or normal sounds will not
initiate an ALARM SIGNAL; however, noise
above the preset level or a sufficient accumulation
of impulses will initiate an alarm.
PERCENTAGE SUPERVISION.-A method
of LINE SUPERVISION in which the current in
or resistance of a supervised line is monitored for
 changes.
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When the change exceeds a selected tric cell. Smoke between the light source and the
percentage of the normal operating current or
resistance in the line, an ALARM SIGNAL is
produced.
PERIMETER ALARM SYSTEM.-An alarm
system which provides perimeter protection.
PERIMETER PROTECTION.-Protection of
access to the outer limits of a PROTECTED
AREA, by means of physical barriers, sensors on
physical barriers, or exterior sensors not associ-
ated with a physical barrier.
PERMANENT CIRCUIT.-An ALARM
CIRCUIT which is capable of transmitting an
ALARM SIGNAL whether the alarm control is in
ACCESS MODE or SECURE MODE. Used, for
example, on foiled fixed windows, TAMPER
SWITCHES, and supervisory lines. See also SU-
PERVISORY ALARM SYSTEM, SUPERVI-
SORY CIRCUIT, and PERMANENT PRO-
TECTION.
PERMANENT PROTECTION.-A system
of alarm devices such as FOIL, BURGLAR
ALARM PADS, or LACINGS connected in a
permanent circuit to provide protection whether
the CONTROL UNIT is in the ACCESS MODE
or SECURE MODE.
PHOTOELECTRIC ALARM SYSTEM.-An
alarm system which employs a light beam and
PHOTOELECTRIC SENSOR to provide a line of
protection. Any interruption of the beam by an
intruder is sensed by the sensor. Mirrors may be
used to change the direction of the beam. The
maximum beam length is limited by many fac-
tors, some of which are the light source intensity,
number of mirror reflections, detector sensitivity,
BEAM DIVERGENCE, fog, and haze.
PHOTOELECTRIC ALARM SYSTEM,
MODULATED.-A photoelectric alarm system
in which the transmitted light beam is modu-
lated in a predetermined manner and in which
the receiving equipment will signal an alarm
unless it receive the properly modulated light.
PHOTOELECTRIC BEAM TYPE SMOKE
DETECTOR.-A SMOKE DETECTOR which
has a light source which projects a light beam
across the area to be protected onto a photoelec-
receiving cell reduces the light reaching the cell,
causing actuation.
PHOTOELECTRIC DETECTOR.-See
PHOTOELECTRIC SENSOR.
PHOTOELECTRIC SENSOR.-A device
which detects a visible or invisible beam of light
and responds to its complete or nearly complete
interruption. See also PHOTOELECTRIC
ALARM SYSTEM and PHOTOELECTRIC
ALARM SYSTEM, MODULATED.
PHOTOELECTRIC SPOT TYPE SMOKE
DETECTOR.-A SMOKE DETECTOR which
contains a chamber with covers which prevent the
entrance of light but allow the entrance of smoke.
The chamber contains a light source and a photo-
sensitive cell so placed that light is blocked from
it. When smoke enters, the smoke particles scat-
ter and reflect the light into the photosensitive
cell, causing an alarm.
POINT PROTECTION.-See SPOT PRO-
TECTION.
POLICE CONNECTION.-The direct link
by which an alarm system is connected to an
ANNUNCIATOR installed in a police station.
Examples of a police connection are an ALARM
LINE, or a radio communications channel.
POLICE PANEL.-See POLICE STATION
UNIT.
POLICE STATION UNIT.-An ANNUN-
CIATOR which can be placed in operation in a
police station.
PORTABLE DURESS SENSOR.-A device
carried on a person which may be activated in an
emergency to send an ALARM SIGNAL to a
MONITORING STATION.
PORTABLE INTRUSION SENSOR.-A
sensor which can be installed quickly and which
does not require the installation of dedicated
wiring for the transmission its ALARM SIG-
NAL.
POSITIVE NONINTERFERING (PNI)
AND SUCCESSIVE ALARM SYSTEM.-An
alarm system which employs multiple alarm
transmitters on each ALARM LINE (like Mc-
CULLOH LOOP) such that in the event of simul-
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taneous operation of several transmitters, one of PROTECTIVE SCREEN.-See GRID.
them takes control of the alarm line, transmits its
full signal, then, release the alarm line for succes-
sive transmission by other transmitters which are
held inoperative until they gain control.
PRESSURE ALARM SYSTEM.-An alarm
system which protects a vault or other enclosed
space by maintaining and monitoring a predeter-
mined air pressure differential between the inside
and outside of the space. Equalization of pressure
resulting from opening the vault or cutting
through the enclosure will be sensed and will
initiate an ALARM SIGNAL.
PRINTING RECORDER.-An electrome-
chanical device used at a MONITORING STA-
TION which accepts coded signals from alarm
lines and converts them to an alphanumeric
printed record of the signal received.
PROPRIETARY ALARM SYSTEM.-An
alarm system which is similar to a CENTRAL
STATION ALARM SYSTEM except that the
ANNUNCIATOR is located in a constantly
manned guard room maintained by the owner for
his own internal security operations. The guards
monitor the system and respond to all ALARM
SIGNALS or alert local law enforcement agencies
or both.
PROTECTED AREA.-An area monitored by
an alarm system or guards, or
suitable barrier.
enclosed by a
PROTECTED PORT.-A point of entry such
as a door, window, or corridor which is moni-
tored by sensors connected to an alarm system.
PROTECTION DEVICE.-(1) A sensor such
as a GRID, FOIL, CONTACT, or PHOTO-
ELECTRIC SENSOR connected into an INTRU-
SION ALARM SYSTEM. (2) A barrier which
inhibits INTRUSION, such as a grille, lock,
fence or wall.
PROTECTION, EXTERIOR PERIME-
TER.-A line of protection surrounding but
somewhat removed from a facility. Examples are
fences, barrier walls, or patrolled points of a
perimeter.
PROTECTION OFF.-See ACCESS MODE.
PROTECTION ON.-See SECURE MODE.
PROTECTIVE SIGNALING.-The initia-
tion, transmission, and reception of signals in-
volved in the detection and prevention of prop-
erty loss due to fire, burglary, or other destruc-
tive conditions. Also, the electronic supervision
of persons and equipment concerned with this
detection and prevention. See also LINE SUPER-
VISION and SUPERVISORY ALARM SYS-
TEM.
PROXIMITY ALARM SYSTEM.-See CA-
PACITANCE ALARM SYSTEM.
PUNCHING REGISTER.-See REGISTER,
PUNCH.
RADAR ALARM SYSTEM.-An alarm sys-
tem which employs RADIO FREQUENCY MO-
TION DETECTORS.
RADAR (RADIO DETECTING AND
RANGING).-See RADIO FREQUENCY MO-
TION DETECTOR.
RADIO FREQUENCY INTERFERENCE
(RFI).-ELECTROMAGNETIC INTERFER-
ENCE in the radio frequency range.
RADIO FREQUENCY MOTION DETEC-
TOR.-A sensor which detects the motion of an
intruder through the use of a radiated radio fre-
quency electromagnetic field. The device operates
by sensing a disturbance in the generated RF field
caused by intruder motion, typically a modula-
tion of the field referred to as a DOPPLER EF-
FECT, which is used to initiate an ALARM
SIGNAL. Most radio frequency motion detectors
are certified by the FCC for operation as "field
disturbance sensors" at one of the following fre-
quencies: 0.915 GHz (L-Band), 2.45 GHz (S-
Band), 5.8 GHz (X-Band), 10.525 GHz (X-
Band), and 22. 125 GHz (K-Band). Units operat-
ing in the MICROWAVE FREQUENCY range
are usually called MICROWAVE MOTION DE-
TECTORS.
REED SWITCH.-A type of MAGNETIC
SWITCH consisting of contacts formed by two
thin moveable magnetically actuated metal vanes
or reeds, held in a normally open position within
a sealed glass envelope.
REGISTER.-An electromechanical device
 Approved For Release 2007/05/11 CIA-RDP96B01172R000700140003-8
which marks a paper tape in response to signal TER PROTECTION, which responds to minute
impulses received, from transmitting circuits. A vibrations of the earth generated as an intruder
register may be driven by a prewound spring walks or drives within its DETECTION
mechanism, an electric motor, or a combination RANGE.
of these. SENSOR.-A device which is designed to
REGISTER, INKING.-A register which produce a signal or offer indication in response to
marks the tape with ink. an event or stimulus within its detection zone.
REGISTER, PUNCH.-A register which SENSOR, COMBUSTION.-See IONIZA-
marks the tape by cutting holes in it. TION SMOKE DETECTOR, PHOTOELEC-
REGISTER, SLASHING.-A register which TRIC BEAM TYPE SMOKE DETECTOR,
marks the-tape by cutting V-shaped slashes in it. PHOTOELECTRIC SPOT TYPE SMOKE DE-
REMOTE ALARM.-An ALARM SIGNAL TECTOR and RESISTANCE BRIDGE SMOKE
which is transmitted to a remote MONITOR- DETECTOR.
ING STATION. See also LOCAL ALARM. SENSOR, SMOKE.-See IONIZATION
REMOTE STATION ALARM SYSTEM.- SMOKE DETECTOR, PHOTOELECTRIC
An alarm system which employes remote BEAM TYPE SMOKE DETECTOR, PHOTOE-
ALARM STATIONS usually located in building LECTRIC SPOT TYPE SMOKE DETECTOR
hallways or on city streets. and RESISTANCE BRIDGE SMOKE DETEC-
REPORTING LINE.-See ALARM LINE. TOR.
RESET.-To restore a device to its original SHUNT.-(1) A deliberate shorting-out of a
(normal) condition after an alarm or trouble sig- portion of an electric circuit. (2) A key-operated
nal. switch which removes some portion of an alarm
RESISTANCE BRIDGE SMOKE DETEC- system for operation, allowing entry into a PRO-
TOR.-A SMOKE DETECTOR which responds TECTED AREA without initiating an ALARM
to the particles and moisture present in smoke. SIGNAL. A type of AUTHORIZED ACCESS
These substances reduce, the resistance of an elec- SWITCH.
trical bridge grid and cause the detector to re- SHUNT SWITCH.-See SHUNT.
spond. SIGNAL RECORDER.-See REGISTER.
RETARD TRANSMITTER.-A CODED SILENT ALARM.-A REMOTE ALARM
TRANSMITTER in which a delay period is in- without an obvious local indication that an alarm
troduced between the time of actuation and the has been transmitted.
time of signal transmission. SILENT ALARM SYSTEM.-An alarm sys-
RFI.-RADIO FREQUENCY INTERFER- tem which signals a remote station by means of a
ENCE. silent alarm.
Rf MOTION DETECTOR. -See RADIO SINGLE CIRCUIT SYSTEM.-An ALARM
FREQUENCY MOTION DETECTOR. CIRCUIT which routes only one side of the
ROBBERY.-The felonious or forcible taking circuit through each sensor. The return may be
of property by violence, threat, or other overt through either ground or a separate wire.
felonious act in the presence of the victim. SINGLE-STROKE BELL.-A bell which is
SECURE MODE.-The condition of an alarm struck once each time its mechanism is activated.
system in which all sensors and CONTROL SLASHING REGISTER.-See REGISTER,
UNITS are ready to respond to an intrusion. SLASHING.
SECURITY MONITOR.-See ANNUNCIA- SMOKE DETECTOR.-A device which de-
TOR. tects visible or invisible products of combustion.
SEISMIC SENSOR.-A sensor, generally bur- See also IONIZATION SMOKE DETECTOR,
ied under the surface of the ground for PERIME- PHOTOELECTRIC BEAM TYPE SMOKE DE-
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TECTOR, PHOTOELECTRIC SPOT TYPE
SMOKE DETECTOR, and RESISTANCE
BRIDGE SMOKE DETECTOR.
SOLID STATE.-(1) An adjective used to de-
scribe a device such as a semiconductor transistor
or diode. (2) A circuit or system which does not
rely on vacuum or gas-filled tubes to control or
modify voltages and currents.
SONIC MOTION DETECTOR.-A sensor
which detects the motion of an intruder by his
disturbance of an audible sound pattern generated
within the protected area.'
SOUND SENSING DETECTION SYS-
TEM.-An alarm system which detects the audi-
ble sound caused by an attempted forcible entry
into a protected structure. The system consists of
microphones and a CONTROL UNIT containing
an amplifier, ACCUMULATOR, and a power
supply. The unit's sensitivity is adjustable so that
ambient noises or normal sounds will not initiate
an ALARM SIGNAL. However, noises above this
preset level or a sufficient accumulation of impul-
ses will initiate an alarm.
SOUND SENSOR.-A sensor which responds
to sound; a microphone.
SPACE PROTECTION.-See AREA PRO-
TECTION.
SPOOFING.-The defeat or compromise of
an alarm system by "tricking" or "fooling" its
detection devices such as by short circuiting part
or all of a series circuit, cutting wires in a parallel
circuit, reducing the sensitivity of a sensor, or
entering false signals into the system. Spoofing
contrasts with CIRCUMVENTION.
SPOT PROTECTION.-Protection of objects
such as safes, art objects, or anything of value
which could be damaged or removed from the
premises.
SPRING CONTACT.-A device employing a
current-carrying cantilever spring which moni-
tors the position of a door or window.
STANDBY POWER SUPPLY.-Equipment
which supplies power to a system in the event the
primary power is lost. It may consist of batteries,
charging circuits, auxiliary motor generators or a
combination of these devices.
STRAIN GAUGE ALARM SYSTEM.-An
alarm system which detects the stress caused by
the weight of an intruder as he moves about a
building. Typical uses include placement of the
strain gauge sensor under a floor joist or under a
stairway tread.
STRAIN GAUGE SENSOR.-A sensor
which, when attached to an object, will provide
an electrical response to an applied stress upon
the object, such as a bending, stretching or com-
pressive force.
STRAIN SENSITIVE CABLE.-An electrical
cable which is designed to produce a signal when-
ever the cable is strained by a change in applied
force. Typical uses including mounting it in a
wall to detect an attempted forced entry through
the wall, or fastening it to a fence to detect
climbing on the fence, or burying it around a
perimeter to detect walking or driving across the
perimeter.
SUBSCRIBER'S EQUIPMENT.-That por-
tion of a CENTRAL STATION ALARM SYS-
TEM installed in the protected premises.
SUBSCRIBER'S UNIT.---A CONTROL
UNIT of a CENTRAL STATION ALARM SYS-
TEM.
SUPERVISED LINES.-Interconnecting lines
in an alarm system which are electrically super-
vised against tampering. See also LINE SUPER-
VISION.
SUPERVISORY ALARM SYSTEM.-An
alarm system which monitors conditions or per-
sons or both and signals any deviation from an
established norm or schedule. Examples are the
monitoring of signals from guard patrol stations
for irregularities in the progression along a pre-
scribed patrol route, and the monitoring of pro-
duction or safety conditions such as sprinkler
water pressure, temperature, or liquid level.
SUPERVISORY CIRCUIT.-An electrical
circuit or radio path which sends information on
the status of a sensor or guard patrol to an
ANNUNCIATOR. For INTRUSION ALARM
SYSTEMS, this circuit provides LINE SUPER-
VISION and monitors TAMPER DEVICES. See
also SUPERVISORY ALARM SYSTEM.
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SURREPTITIOUS.-COVERT, hidden,
concealed, or disguised.
SURVEILLANCE.-(1) Control of premises
for security purposes through alarm systems,
closed circuit television (CCTV), or other moni-
toring methods. (2) Supervision or inspection of
industrial processes by monitoring those condi-
tions which could cause damage if not corrected.
See also SUPERVISORY ALARM SYSTEM.
TAMPER DEVICE.-(1) Any device, usually
a switch, which is used to detect an attempt to
gain access to intrusion alarm circuitry, such as
by removing a switch cover. (2) A monitor circuit
to detect any attempt to modify the alarm circui-
try, such as by cutting a wire.
TAMPER SWITCH.-A switch whch is in-
stalled in such a way as to detect attempts to
remove the enclosure of some alarm system com-
ponents such as control box doors, switch covers,
junction box covers, or bell housings. The alarm
component is then often described as being
"tampered".
TAPE.-See FOIL.
TAPPER BELL.-A SINGLE-STROKE BELL
designed to produce a sound of low intensity and
relatively high pitch.
TELEPHONE DIALER, AUTOMATIC.-A
device which, when activated, automatically dials
one more pre-programmed telephone numbers
(e.g., police, fire department) and relays a re-
corded voice or coded message giving the location
and nature of the alarm.
TELEPHONE DIALER, DIGITAL.-An au-
tomatic telephone dialer which sends its message
as a digital code.
TERMINAL RESISTOR.-A resistor used as
a TERMINATING DEVICE.
TERMINATING CAPACITOR.-A capaci-
tor sometimes used as a terminating device for a
CAPACITANCE SENSOR antenna. The capaci-
tor allows the supervision of the sensor antenna,
especially if a long wire is used as the sensor.
TERMINATING DEVICE .-A device which
is used to terminate an electrically supervised
circuit. It makes the electrical circuit continuous
and provides a fixed IMPEDANCE reference (end
of line resistor) against which changes are meas-
ured to detect an ALARM CONDITION. The
impedance changes may be caused by a sensor,
tampering, or circuit trouble.
TIME DELAY.-See ENTRANCE DELAY
and EXIT DELAY.
TIME DIVISION MULTIPLEXING
(TDM).-See MULTIPLEXING, TIME DIVI-
SION.
TIMING TABLE.-That portion of CEN-
TRAL STATION equipment which provides a
means for checking incoming signals from Mc-
CULLOH CIRCUITS.
TOUCH SENSITIVITY.-The sensitivity of a
CAPACITANCE SENSOR at which the ALARM
DEVICE will be activated only if an intruder
touches or comes in very close proximity (about 1
cm or 1/2 in.) to the protected object.
TRAP.-(1) A device, usually a switch, in-
stalled within a protected area, which serves as
secondary protection in the event a PERIMETER
ALARM SYSTEM is successfully penetrated. Ex-
amples are a TRIP WIRE SWITCH placed across
a likely path for an intruder, a MAT SWITCH
hidden under a rug, or a MAGNETIC SWITCH
mounted on an inner door. (2) A VOLUMETRIC
SENSOR installed so as to detect an intruder in a.
likely traveled corridor or pathway within a secu-
rity area.
TRICKLE CHARGE.-A continuous direct
current, usually very low, which is applied to a
battery to maintain it at peak charge or to re-
charge it after it has been partially or completely
discharged. Usually applied to nickel cadmium
(NICAD) or wet cell batteries.
TRIP WIRE SWITCH.-A switch which is
actuated by breaking or moving a wire or cord
installed across a floor space.
TROUBLE SIGNAL.-See BREAK ALARM.
UL.-See UNDERWRITERS LABORATO-
RIES, INC.
UL CERTIFICATED.-For certain types of
products which have met UL requirements, for
which it is impractical to apply the UL Listing
Mark or Classification Marking to the individual
product, a certificate is provided which the man-
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ufacturer may use to identify quantities of mate-
rial for specific job sites or to identify field in-
stalled systems.
UL LISTED.-Significes that production sam-
ples of the product have been found to comply
with established Underwriters Laboratories re-
quirements and that the manufacturer is autho-
rized to use the Laboratories' Listing Marks on
the listed products which comply with the re-
quirements, contingent upon the follow-up ser-
vices as a check of compliance.
ULTRASONIC.-Pertaining to a sound wave
having a frequency above that of audible sound
(approximately 20,000 Hz). Ultrasonic sound is
used in ultrasonic detection systems.
ULTRASONIC DETECTION SYSTEM.-
See ULTRASONIC MOTION DETECTOR and
PASSIVE ULTRASONIC ALARM SYSTEM.
ULTRASONIC FREQUENCY.-Sound fre-
quencies which are above the range of human
hearing; approximately 20,000 Hz and higher.
ULTRASONIC MOTION DETECTOR.-A
sensor which detects the motion of an intruder
through the use of ULTRASONIC generating
and receiving equipment. The device operates by
filling a space with a pattern of ultrasonic waves;
the modulation of these waves by a moving object
is detected and initiates an ALARM SIGNAL.
UNDERDOME BELL.-A bell most of whose
mechanism is concealed by its gong.
UNDERWRITERS LABORATORIES, INC.
(UL).-A private independent research and test-
ing laboratory which tests and lists various items
meeting good practice and safety standards.
VIBRATING BELL.-A bell whose mecha-
nism is designed to strike repeatedly and for as
long as it is activated.
VIBRATING CONTACT.-See VIBRA-
TION SENSOR.
VIBRATION DETECTION SYSTEM.-An
alarm system which employs one or more CON-
TACT MICROPHONES or VIBRATION SEN-
SORS which are fastened to the surfaces of the
area or object being protected to detect excessive
levels of vibration. The contact microphone sys-
tem consists of microphones, a CONTROL
UNIT containing an amplifier and an ACCU-
MULATOR, and a power supply. The unit's
sensitivity is adjustable so that ambient noises or
normal vibrations will not initiate an ALARM
SIGNAL. In the vibration sensor system, the
sensor responds to excessive vibration by opening
a switch in a CLOSED CIRCUIT SYSTEM.
VIBRATION DETECTOR.-See VIBRA-
TION SENSOR.
VIBRATION SENSOR.-A sensor which re-
sponds to vibrations of the surface on which it is
mounted. It has a NORMALLY CLOSED
SWITCH which will momentarily open when it
is subjected to a vibration with sufficiently large
amplitude. Its sensitivity is adjustable to allow
for the different levels of normal vibration, to
which the sensor should not respond, at different
locations. See also VIBRATION DETECTION
SYSTEM.
VISUAL SIGNAL DEVICE.-A pilot light,
ANNUNCIATOR or other device which pro-
vides a visual indication of the condition of the
circuit or system being supervised.
VOLUMETRIC DETECTOR.-See VOLU-
METRIC SENSOR.
VOLUMETRIC SENSOR.-A sensor with a
detection zone which extends over a volume such
as an entire room, part of a room, or a passage-
way. ULTRASONIC MOTION DETECTORS
and SONIC MOTION DETECTORS are exam-
ples of volumetric sensors.
WALK TEST LIGHT.-A light on motion
detectors which comes on when the detector sen-
ses motion in the area. It is used while setting the
sensitivity of the detector and during routine
checking and maintenance.
WATCHMAN'S REPORTING SYSTEM.-
A SUPERVISORY ALARM SYSTEM arranged
for the transmission of a patrolling watchman's
regularly recurrent report signals from stations
along his patrol route to a centrol supervisory.
agency.
ZONED CIRCUIT.-A circuit which pro-
vides continual protection for parts or zones of the
PROTECTED AREA while normally used doors
and windows or zones may be released for access.
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ZONES.-Smaller subdivisions into which secure and to permit pinpointing the specific
large areas are divided to permit selective access location from which an ALARM SIGNAL is
to some zones while maintaining other zones transmitted.
 Approved For Release 2007/05/11 : CIA-RDP96B01172R000700140003-8
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LAW ENFORCEMENT ASSISTANCE ADMINISTRATION
WASHINGTON. 0 C. 20531
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