Glossary - CCTV, Intruder Alarm and access Control

CCTV Glossary

Compression Techniques are used in Digital CCTV to reduce the file sizes
of recorded video images. Typical compression formats used for video are:
MJPEG, MPEG-4 & H.264.

Day/Night Camera: A camera that is 'Day/Night' means it can capture video in both day and
nighttime.
In low light conditions, the Day/Night chipset switches from colour
to black & white at night to enhance the picture quality

DVR: Digital Video Recorder - CCTV Footage is converted to a digital signal
and stored on a PC Hard Disk. This is now the standard CCTV recording
practice.

Field of View: The view of the camera - in relation to the angle of view and distance
of the object from the lens

Frame Rate: The quality of a Digital Surveillance Systems is often determined by
the Total Frame Rate it can record at. The higher the Frame Rate, the
higher the quality of recording and the more Real Time your CCTV recording
will be - Real Time recording for 1 camera is 25 Frames Per Second (PAL).

IP Camera: A CCTV Camera that can transmit video and audio over TCP/IP network.An IP Camera can connect to a local network and streams it's video overthe network to a Network Video Recorder.IP Cameras can come with additional features including Power over Ethernet, wireless lan connection and Mega Pixel Resolution

IR Cut Filter: An IR Cut Filter is an extra filter inside the camera that moves behind
the camera lens when it gets dark. A camera with an IR Cut Filter will
produce very high quality images in low light conditions.

Motion Detection: Recording method for digital surveillance systems. When someone walks
in front of a camera, the pixels change and the DVR defines this as motion.
The surveillance system will then record these images to the hard disk.
This is a popular recording setup as every event recorded is actually
motion driven as opposed to a static image if the system was set to record
'round-the-clock'.

Mega Pixel resolution refers to video resolutions now achievable using IP Cameras . Unlike Analogue cameras, whose resolution is usually limited to around752 x 582 (0.4 Mega Pixels), a Mega Pixel IP Camera can achieve fargreater resolutions such as 1280 x 1024 (1.3 Mega Pixels) or 1600 x1280 (2 Mega Pixels).
This increase in resolution produces far better image quality than a traditional analogue camera could ever achieve.

Power Over Ethernet is a method by which power is tramitted over aCAT-5/6 cable. This is often used with the installation of IP Camerassaving time/money by reducing cabling. An IP Device would need to be fitted with a PoE RJ45 port to use this functionality.

PTZ: Pan Tilt Zoom - a camera which can be controlled via Joystick or DVR
and moved up/down, left/right and zoomed in/out.

Intruder Alarm Glossary

Infra-Red: The area below the visible spectrum. B&W cameras are very sensitive to infrared light and allow the useof infrared illuminators to enhance poorly lit locations without alerting subjects during surveillance. Colorcameras are also sensitive to infrared light, but require an infrared filter to filter out the red light tokeep the image colors.

Television Lines (TVL): This is a measure of the resolution of a video device. The higher thenumber, the higher the resolution is. 380 TVL is considered mediumresolution. 480 TVL or greater is considered high resolution.

A Network Video Recorder (NVR) is a digital device which sits on yourIP CCTV network to recieve live image/video streams and record themdigitally to a hard disk.

Keypad: This device normally goes inside the front door. It is where you set the alarm and disarm it using your personal code. It will have a display which informs you of any events related to the system which may have occured.

Control Panel: This box contains the 'brain' of the alarm system and is usually located beside your electrical fuse board.You will never have to go near this panel as it should only be accessed by the alarm installer.

Panic Button: This is a device which, when pressed, activates the alarm. The alarm keypad contains a panic button feature on it as standard. Additional panic buttons can be installed if required.

Alarm Cables: These are the wires which are installed during construction throughout your home for the alarm system. Wires should be visible on your windows and doors and anywhere else where alarm devices will be located. The cables should be the same colour as the frames of the windows and doors.

Licensed Installer: Any installer which has a license from the Private Security Authority (PSA), the body set up by the Irish government to regulate the home security industry.

Monitoring: When a home security system is connected by GSM/PSTN Line to a Cerified monitoring station.

External Bell: This is the bell that rings outside your home when the alarm is triggered. It is usually placed high up near the eves at the front of the house. Modern external bells come with a flashing strobe light and self contained back up battery. They also should have a permanent visible light on to tell the public that you have an active alarm system.

Magnetic Contact: These consist of 2 parts, the magnet and the contact. The magnet is placed on the part of the window or door that opens. The contact is placed on the frame and connected into the alarm cable circuit. When the window or door opens and the magnet moves away, it opens the circuit and sends a signal to the alarm control panel.

Shock Sensors: Also known as vibration sensors or inertia sensors, these devices contain a tremble switch. When a window or door is tampered with by an intruder the switch trembles and breaks the circuit, sending a signal to the control panel.
The device can monitor the extent of the vibration and thus be programmed to ignore false vibrations caused by the wind for example,and only activate the alarm when genuine attacks occur.

PIR's: Also known as Passive Infrared detectors(PIRs).These devices are used to pick up infrared heat from the human body. When placed in the corner of a room they will see any movement and report it to the control panel. They cannot normally be used in areas where pets move about as they will see them also.

Internal Sounder: This is a simple alarm bell which rings loudly upon alarm activation. It can be programed to ring for a set length of time which is normally 15 minutes.

Back-up Battery: The alarm system contains a 12v back up batterywhich keeps it active in the event of an electrical outage for about 2days. When the power comes back on the battery will recharge itselfautomatically.

Quad/Dual PIR's: The thermal sensor used in today's PIRs is actually two (dual) or four sensors (quad) in a single unit. The two-element device, which is commonly called a Dual PIR (not to be confused with dual-tech which is a combination PIR and microwave sensor-both technologies have to trip before the unit goes into alarm)., divides each zone into two distinct, side-by-side detection areas. A person moving will first activate one of these sensors and then the other. This allows the PIR to reject alarms that originate from heated surfaces or even RF interference, since both of these are detected simultaneously by both elements.

EN50131 is a collection of different standardsdesigned to cover the design and installation of all aspects ofIntruder and Hold-Up Alarm Systems.

The Private Security Authority (PSA), which was established pursuant to the Private Security Services Act 2004, is the statutory body with responsibility for licensing and regulating the private security industry in Ireland.

Access Control Glossary

Anti-Passback: A feature that will not allow any card to re-enter unless it has been used to exit. This requires that readers be used for both entry and exit.

Door forced open: A signal indicating that the door was opened without a valid card or request to exit device. This requires a status switch and some type of rex device.

REX button: A Request to exit button. A device that must be pushed in order to release the door.

Fail safe: Is a locking device that is unlocked when no power is applied.

Fail secure: Is a locking device that is locked when no power is applied. These are not normally used for exit doors since they cannot be unlocked during a power outage.

Break Glass Unit: A device mounted near the exit door that can be used to release the door in the event of an emergency.

Stand alone: A system where the entire system is contained in the card reader.

Time zones: "Schedules" that allow cards to function or not function depending on the time of day. This is used to limit access to the facility. The schedule may include not only time but which days of the week a card is valid.

Biometric systems measure some physical property of the user such as hand geometry, retina pattern, or voice pattern. These type of devices offer very high security but also are the most expensive and require that the user be present in order to be enrolled into the system.

The most common reader is called Proximity. These systems use cards or tokens as a means of identification. As the name implies, no direct contact is required between the card and the reader for the system to operate, the card must only be in the proximity of the reader. The read range will vary depending upon the card/token and the type of reader, from 1/2 inch to up to 33 feet. The reader generates an RF field which causes specially designed wires in the card to resonate, transferring the card information to the reader. These cards are immune to electromagnetic and RF interference, and they can offer "hands free" operation.

Wiegand cards are essentially magnetic field effect devices. As the card is inserted or swiped through the reader an electromagnetic field generated by the reader induces a voltage in the card causing it to transmit its code. Unlike some insertion type systems, wiegand readers are completely sealed against weather conditions and as a result have a long live span. These cards are difficult to duplicate, highly damage resistant, and offer a high level of security, but as with proximity cards expensive, and generally can only be programmed by the manufacturer.

Magnetic stripe cards use the same technology that is employed in credit cards, and are probably the most common type of card in use. There are two types of magnetic cards, low-coercivity and high-coercivity. The high-coercivity type are less prone to accidental erasure and damage. Magnetic stripe cards require that the card come in direct contact with the reader head causing wear and a shorter life span. This direct contact requirement also can cause misreads due to dirt and debris accumulation in the reader. Certain access control systems allow the user to utilize their existing credit cards, eliminating the need to purchase cards. The cards are low in cost but are easily duplicated, are affected by outside magnetic fields, and the readers require occasional cleaning to remove any dirt buildup on the read heads.

Keypads use a numeric pad, similar to that of a telephone. The user simply presses his code into the keypad and the system reads the numbers. This system does not require the user to carry any special card or token but can less secure since unless the user is very careful someone may see which numbers are being pressed. Certain keypads overcome this drawback by scrambling the number layout each time the keypad is used. Keypads can be use either by themselves or for high security in conjunction with some card reader technology. In this manner the user must both present a card and enter a code before access is granted.

Magnetic Lock : A door lock made upof an electromagnet and a strike plate. The electromagnet is mounted inthe door frame; the strike plate in the door. When power is applied tothe electromagnet, the strength of the electromagnet keeps the doorlocked.

Status switch: A magnetic contact mounted on the controlled door. It is used to detect door held or door forced.

Auto-Iris Lens is a lens with a built-in method of automatically controlling the lens aperture for the best video quality under diverse and changing lighting conditions. Auto-iris lenses can be especially helpful under very low light and bright direct forward light. In order to use an auto-iris lens, however, the video camera you are using must have a built-in auto-iris port to supply the lens with a small amount of DC electical voltage. Manual iris lenses are also available and do not require any special ports or cable connections