Specifications

126 VISTA AT A GLANCE V5 - FOR MORE INFORMATION VISIT: V I S T A - C C T V. C O M / I P
GLOSSARY OF TERMS
PPP (Point-To-Point Protocol) - A data-link protocol that provides
dialup access over serial lines by encapsulating protocols in specialised
Network Control Protocol packets. These packets can be used to replace
a network adapter driver which allows remote users to log on to the
network as if they were in-house.
Presets - The pre-positioning of pan, tilt and zoom cameras by the
use of potentiometers in the moving parts of the camera head. These
allow the control equipment to store and move to a set reference point
when the controller dictates or when an alarm exists. Special telemetry
equipment is required.
Privacy Zones - The ability to mask out a specific area to prevent it
from being viewed or recorded.
Progressive Scan - Progressive scan, as opposed to interlaced video,
scans the entire picture, line by line every sixteenth of a second.
PROM - Programmable Read Only Memory.
Protocol - A special set of rules governing how two entities will
communicate.
Protocol Converter - Data transmission converter i.e. RS232 to RS485
or vice versa.
PSTN (Public Switched Telephone Network) - Any switching
communication system- such as Telex, TWX or public telephone
networks- that provides circuit switching to many customers.
PSU - Power Supply Unit.
Pulse - A positive or negative change in voltage that conveys
information to a circuit.
QCIF (Quarter Common Immediate Format) - refers to the analogue
video resolution 176x144 pixels. Also see Resolution.
Quad Splitter - Device that uses digital techniques to compress four full
pictures onto one monitor screen.
Rack Mount (19” rack) - An industrial standard housing 19” wide, its
height is measured in units (Us) of 1.75”.
Radio Frequency (RF) - Signals with a repetition rate above audible
range, but below the frequencies associated with heat and light.
RAID (Redundant Array of Independent Disks) - This a technology of
connecting a number of hard drives into one mass storage device, which
can be used, among other things, for digital recording of video images.
RAM (Random Access Memory) - Read/write memory of a computer.
Usually a memory chip that can be written to, read from and erased
from.
Range Finder - Used to determine the focal length needed and what the
picture will look like on the monitor. The user looks through the device
and adjusts the range finder to the desired picture. Numbers on the
outside of the range finder indicate the focal length needed.
RCA Connector - The type of jacks used by most stereo equipment and
VCRs - audio and composite video input.
Refresh Rate - The number of times per second a displayed image is
regenerated. Measured in Hertz, e.g, 60Hz or 60 times per second. The
faster the rate, the steadier the image.
Relay - A magnetically operated mechanical switch.
Remote Access - The ability of a computer in one location to connect
to a device at another location or site.
Remote Access Server - A computer or self-contained unit that
provides remote dialup access to a LAN through modems and/or ISDN
adapters.
Remote Control - A transmitting and receiving of signals for controlling
remote devices such as pan and tilt units, lens functions, wash and wipe
control and similar. It may also refer to the hand held controls for some
VCRs and other CCTV equipment.
Remote Set-up (Cameras) - The ability to set-up the cameras
operational features, with the ease of OSD, compatible via co-axial
telemetry transmitters, without the need for telemetry receiver. No extra
cabling is required.
Resolution - A measure of the ability of a camera or television system
to reproduce detail. Typically refers to the number of picture elements
that can be reproduced with good definition. The larger the number of
pixels the higher the resolution, creating finer and smoother images
when displayed. Higher resolutions allow more information to be
displayed on the same size screen.
VGA = 640x480, SVGA = 800x600
XGA = 1024x768, Wide XGA = 1366x768
SXGA = 1280x1024, SXGA+ = 1400x1050
UXGA = 1600x1200
Ripple - Amplitude variations in the output voltage of a power supply
caused by insufficient filtering.
Roll - A loss or weakening of vertical sync which causes the picture to
move up or down on the TV screen.
Router - A system that stores and forwards data packets - by way of
network addresses - from one LAN to WAN to another.
RG-59 - A video coaxial cable with 75Ohm characteristic impedance. A
type of coaxial cable that is most common in use in small to medium-
size CCTV systems. It has an outer diameter of approx. 6mm and it is
a good compromise between maximum distances achievable (up to
250m) and good transmission.
RGB (Red, Green, Blue) - These three colours represent the entire colour
spectrum.
Router - A device that determines the next network point to which a
packet should be forwarded on its way to its final destination.
RS232 - A commonly used computer serial interface.
RS422 - EIA interface standard that generally operates in conjunction
with RS-449 and specifies electrical characteristics for balanced circuits
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.
RS485 - Balanced interface similar to RS-422/V.11 but using tri-state
drivers for multidrop applications.
RTP (Real-Time Transport Protocol) - RTP is an Internet protocol for the
transport of real-time data, e.g. audio and video.
Rugby Clock - Radio signal to synchronize equipment clocks accurately
and that automatically adjusts the BST setting.
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.