Product guide

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Glossary of T
er
ms
RS-422
EIA inter
face standard that generally operates in conjunction with RS-
449 and specifies electrical characteristics for balanced cir
cuits and
extends transmission speeds and distances beyond RS-232/V
.24. RS-
422 is a balanced voltage system with a high level of noise immunity.
RS-485
Balanced inter
face similar to RS-422/V.11 but using tri-state drivers for
multidr
op applications.
RS232
A commonly used computer serial interface.
RS232
A data communication industry standar
d for the serial transmission of
infor
mation. Distance without modems is limited.
RS485
A data communication industry standar
d for transmission of
information.
Rugby Clock
Radio signal to synchronize equipment clocks accurately and that
automatically adjusts the BST setting.
S-VHS (Super VideoHome System)
New format high resolution VHS video recorders, capable of giving
gr
eatly improved picture if all features are used. VHS compatible.
S-VHS+
A r
ecording system that can playback a picture with a resolution of
over 410 TVL.
S.E.C.AM. (Systeme Electronique Couleur Avec Memoire. See CCIR)
Colour TV system used in France.
S/N Ratio (Signal to Noise Ratio)
Measure of noise levels of a video signal; the higher the number the
better.
Scanner
A pan only unit.
SCART
Standard European 20 pin connector used for carrying both video
and audio signals in domestic TV appliances, now utilised on some
CCTV equipment.
Shutter
An electronic circuit available on many CCD cameras. Allowing the
light gathering period (1/50th of a second) of the camera to be
stopped prematurely (as little as 100,000 of a second).
Simplex (Multiplexer)
A multiplexer with 1 frame stor
e that can either time multiplex r
ecor
ds
or show multi-screen pictures in live or play back. It cannot record the
multiplexer pictures whilst showing multi-screen pictures.
Single-Mode Fibre
An optical fibre that supports only one mode of light propagation
above the cut off wavelength. The core diameters are usually
between 5 and 10 micr
ometr
es (um).
Swivel Mount
Used on a tower or bracket to enable the housing to be pointed at
any angle, vertically or horizontally.
Sync (Synchronisation pulses)
Pulses generated, normally by the camera, to tell other pieces of
equipment when a picture (field sync) or one line of a picture (line
sync) is to start.
Telemetry
A system utilising 'control code' transmitters and receivers. These use
the video cable or a simple twisted pair cable to send their
information.
Terminated (75 Ohm terminated)
Video input of a piece of CCTV equipment, wired to be the last in a
particular video line.
TFT
Thin Film T
ranslator. A type of flat screen display.
Time-Lapse VCR
Video recorder that can record frames with pauses between them
ther
eby extending the time that a standard length tape will last.
T
imebase Corrector (T.B.C.)
Electronic circuit that aligns unsynchronised video signals before
signal pr
ocessing. Used in multiplexers and quad splitters.
T
riplex™
Multiplexer featur
e that gives you the ability to simultaneously view
both playback and live cameras within the same multi-screen, while
still encoding.
TVL (T
elevision Lines - Resolution)
The maximum number of changes between light and dark on a
picture across 3/4 of the width dictates the resolution of a CCTV
pr
oduct, measured in TVL.
Unmonitor
ed
Does not sense the open/closed state of the door.
Unter
minated (Hi-Z)
V
ideo input of a piece of CCTV equipment, wired so as to allow the
video signal to be fed to further equipment. Does not necessarily
include extra sockets for the extra coaxial cables.
Update Rate
The number of pictur
es (fields) per second recorded by timelapse
VCRs/Multiplexers or HDRs. USB (Universal Serial Bus) Serial 4-wire bus
architecture for peripherals I/O ports; autosenses up to 128 peripherals
at a distance of 5 metr
es and at a maximum data rate of 12 Mbps.
User Friendly
The term applied to software and/or hardware that has been
designed to be used easily without having to remember complex
procedur
es.
V.B.S. (Video,Burst, Sync)
A composite colour video signal.
V.H.S. (Video Home System)
Name given to 1/2" tape format domestic video recorder.
V.S. (Video Sync)
A composite monochrome video signal.
Varifocal
A type of lens which enables a manual selection between two focal
lengths to give the desired picture view.
Vertical Interval Switching
Sequential switchers waiting until the current field has finished before
they display the next camera, even though the dwell time has
elapsed.
VEXT
A multiplexer featur
e that uses a pulse generated by the VCR so that
the multiplexer automatically adjusts to the VCR time lapse speed.
Video Motion Detection (V.M.D.)
A system that uses the video signal fr
om a camera to determine if
ther
e is any movement in the picture and set of an alarm.
WAN (Wide Area Network)
A data-communications network spread across a wide geographic
area and incorporating a large number of users. A WAN often uses
transmission devices provided by common carriers. Examples of WANs
include Frame Relay, SMDS and X.25.
Wavelets™
A suite of digital compression tools that is becoming popular in the
CCTV industry, giving good pictur
e quality at higher compr
ession
rates.
Y
The black and white video signal.
Y/C
A method of sending video pictures in 2 separate parts down 2
separate cables. The component parts are Y (the Black and White
portion) and C (the colour portion).