Elevator Surveillance Guide

 Elevator Surveillance Guide

Installing surveillance in an elevator can be challenging. Small but wide areas, vandal resistance, and transmission methods all present challenges not found in other areas cameras are installed. In this note, we look at:

• Form factor: Box vs. dome vs. specialty
• Resolution: How much is necessary?
• Transmission: Wired vs. wireless vs laser methods
• Dealing with electrical contractors

Form Factor

The first decision to make when considering elevator cameras is form factor. Minidome and corner mount are the two most common options in use as they most compact compared to box, bullet, or full sized dome cameras. Other form factors, such as box or bullet may be more easily tampered with due to the low ceiling height of the elevators, and more easily knocked out of position.

Minidome

The key advantage to minidomes is camera choice, as most manufacturers offer cameras in this form factor, with numerous resolution and lens options. These options are not generally seen in corner mount cameras.

However, they are more obtrusive than many corner mount housings, and do not blend into the interior of the elevator as well. Where aesthetics are the key concern, domes may not be preferred.

Corner Mount

This type of mount places the camera in a roughly triangular housing made to cover one of the elevator's corners. Some are sold as unitized housing/camera packages, while other manufacturers sell housings meant to accept a box camera. Size and appearance varies depending on manufacturer:

They key drawback to corner mount cameras is limited availability. Most manufacturers do not offer corner mount options, and those that do typically only offer one or two models, with limited resolution and lens choices. Larger corner housings built for box cameras add more flexibility, but are larger and more obtrusive.

Field of View/Resolution

Given elevators' small size, generally under 10' wide, users typically choose to cover the full car instead of just the doors. This gives them not only the opportunity to view comings and goings, tracking subjects throughout a facitity, but to view potential incidents in the elevator, as well. However, care should be taken that pixels per foot (PPF) does not drop below acceptable levels for recognition if no other cameras will provide facial shots of subjects, e.g. lobby and hallway cameras.

For example, using an actual 103° field of view from an elevator camera with Camera Calculator, we can see the difference between VGA, 720p, and 1080p in a typical 8x8' elevator. Estimating ~9' to target to reliably capture subjects as they enter through the elevator doors, 720p provides 56 PPF in this scene. This is likely enough to provide identification quality video under good lighting. VGA provides only 28 PPF, too low for recognition, while 1080p provides 85, more than enough.

Mounting Height

Since most people look down while walking, and criminals may actively avoid cameras, mounting height in elevators should be carefully considered for the best chance of capture. As we found cameras are typically best mounted as low as possible, with ~8' being a "sweet spot", better able to see those with heads down or hats on while also see over subjects beneath the camera.

This image shows the effects of mounting height and the subject's face angle, displaying the difference in capture quality at various mounting heights with the subject's face level as well as tilted down.

Signal Transmission

Once the camera has been selected, installers must decide how signal will be carried from the elevator. There are three typical options for this:

• Traveler cable
• RF wireless
• Optical laser

Traveler Cable

Connections between the elevator car and the machine room for power and signal are made via a specialized traveler cable. This cable is attached to the car, typically to the bottom, and to the top or center of the shaft. The construction of this cable varies, but it typically contains multiple twisted pair conductors for power and control, and possibly a UTP or coaxial cable for video. 

This image shows cross-sections of various flat traveler cables:

Generally speaking, since these cables are often attached to the top of the shaft, making the cable approximately twice the height of the shaft, UTP is not a usable solution for Ethernet. Buildings of 12-14 stories can easily have a 300' traveling cable, which exceeds the maximum distance category cables can be run, before even considering horizontal runs to an equipment room or IDF. In low-rise buildings, UTP may be an option, however. Fiber-optic and coaxial cables may be considered otherwise.

RF Wireless

The second option is to opt for wireless connectivity, utilizing a pair of wireless APs between the car and bottom or top of shaft. Both are used in practice, with the bottom of the shaft generally chosen for easier servicing. In this case, local power must be obtained from the car, which may involve the elevator contractor. Power is readily available, however, due to lights and air conditioning installed in the car.

Wireless eliminates the issue of necessary conductors in the traveler cable, but presents challenges of its own. Cables and conduits located in the elevator shaft may cause interference, making wireless connectivity unreliable. Very narrow beamwidth antennas may be used to compensate for this, but antenna alignment must be carefully set and maintained over time.

Optical Wireless

Optical wireless uses a pair of laser transceivers, one mounted to the car, the other in the shaft, to send/receive data. This is specified to handle elevator shafts up to 75 floors.

Optical product performance is degraded by dust, dirt, and other debris which may fall in the elevator shaft and as such should be cleaned regularly.

Dealing With Elevator Contractors

Normally, most facilities maintain service contracts with an elevator contractor, since the elevator must undergo routine maintenance. These contractors may be difficult to deal with, as a number of users have shared. They are often hesitant to modify existing traveling cables for new services, simply because it complicates (however slightly) their routine maintenance of the elevator with a system outside their control. If the traveling cable is insufficient to add video, installing a new cable is, most times, cost prohibitive, and may remove the elevator from service for several days. Both of these add up to expenses users may not wish to incur.

To avoid the coordination and expense required to have the elevator vendor add video to a car, users and integrators may attempt to add their own cable to the car. There are two things to be aware of in this case: 

• Third parties attempting to modify the cable without the contractor's permission will void warranties and service contracts in most cases. Even leaving existing cables alone and simply zip-tying a new UTP cable to it may be frowned upon.
• According to NEC code, hoistway cables must be listed for use in these applications, and be of type E. Standard UTP, fiber, and coaxial cables do not meet these requirements.

 

Fiber cabling with PoE for long-distance IP camera installation

Fiber optic cabling with PoE converters allows long-distance IP camera placement

Power over Ethernet (PoE) technology enables powering IP surveillance cameras through the transfer of DC electrical power along with data over standard unshielded twisted pair (UTP) cabling. This cabling connects to a network device through an RJ-45 port that injects the power from power sourcing equipment such as a PoE switch or midspan PoE injector. PoE provides a flexible and convenient means of powering devices that are located in out-of-the-way locations, and saves money by eliminating the expense and difficulty of direct electrical wiring. A challenge with PoE is reaching remote locations outside the distance limitation of UTP cabling. According to the TIA/EIA 568-5-A standard for category 5e cable, the maximum length for a cable segment is 100 meters (328 ft), and PoE power injectors or midspans do not increase the distance of the data link.

So, how do you get beyond that 100-meter limit? Once answer is through fiber optics. Fiber optic cabling is an effective method to overcome the distance and bandwidth limitations of UTP, and media converters are a commonly used to integrate copper network equipment and fiber. Since DC power cannot be conducted over fiber, PoE media converters are the solution to extend network distances via fiber to remote IP cameras. A PoE media converter converts the fiber to copper, and sends DC power to the camera over the UTP cabling.

How PoE Media Converters Work

On the main article image/PoE schematic that appears at right, an Ethernet switch with RJ-45 ports resides in a control room or data closet. The copper UTP cabling is converted to fiber with a standard media converter. The fiber is run a long distance to the PoE media converter located near a convenient AC or DC power source, where it converts the fiber back to copper UTP. The PoE media converter also functions as a power-sourcing mini switch, and injects PoE (DC power) over the UTP cable. At the other end of the UTP cable is the IP camera, located up to 100 meters away from the PoE media converter.

PoE media converters are available with Gigabit Ethernet and Fast Ethernet data rates and can support PoE (15.4 watts) or PoE+ (25.5 watts). PoE media converters function like PoE mini-switches, and are available in a variety of multi-port configurations, including dual RJ-45 and dual fiber ports. They can support fixed fiber connectors or small form pluggable transceivers.

To understand those power specifications, it’s worth knowing that in 2003, the IEEE ratified the 802.3af PoE Standard. That standard provides up to 15.4 watts of power per port. Late in 2009, the IEEE ratified the 802.3at PoE Standard known as PoE+ that provides up to 25.5 watts of power for each port. PoE+ can be required to power IP cameras with Pan-Tilt-Zoom (PTZ) capabilities, and weather-hardened cameras used in cold environments.

Key Features to Consider When Selecting a PoE Media Converter:

• PoE+ to future proof applications

• Out-of-the-box support for IEEE Alternative A and B, and Legacy Power detection

options (without the need for jumper wires or external cables)

• Jumbo Ethernet Frames to enhance throughput for reliable data flow

• Multiple port configurations for deploying a variety of architectures and topologies:

– Daisy chain media converters or install in ring topology

– Redundant fiber with less than 50ms switch over time

– Dual UTP ports for powering two PoE devices per converter

• Ability to be powered by either AC or DC power source

• Industrial hardened temperature ranges for outdoor applications

• Determines and delivers the specific power level required by the PD

• Fully configurable DIP-switches for easy set up:

– Link Fault Propagation Modes

– PoE Power Reset on fiber Rx loss that automatically resets

Leverage the Benefits of Fiber

There are several solutions available to extend the distances of PoE network links, including LAN extenders that convert Ethernet to DSL, UTP to coax converters and wireless technology. When you’re going long distance, however, fiber optic cabling provides several advantages over these technologies.

Unlike copper, fiber extends network distances up to 87 miles (140 kilometers) per link with no data deterioration over distance (signal deterioration is to be expected in copper cabling). LAN extenders can only extend network distances about 3,300 feet, but a data rate of 100 Mbps can drop by 70 percent at longer distances.

Fiber cabling provides security benefits as well. It is a secure medium that generates no electro-magnetic emission and is very difficult to tap. Fiber is also very reliable because it is not susceptible to electrical interference, or data loss due to temperature or atmospheric conditions.

【Installation Steps】

1) Please turn off the signal source and the device's power, installation with power on may damage the device;
2) Check if the network cable and other transmission line that will be used is occupied by other device;
3) Use a network cable to connect video to POE Ethernet Optical Transceiver's LAN port with PoE IP camera or other PoE network device;
4) Use two single mode double optical fibers to connect two converter's optical port, please attention the optical fiber which connect the RX and TX port should be across; that means one optical fiber, one side is to connect the optical module TX port, the other side should connect the RX port;
5) Check if the installation is correct and device is good, make sure all the connection is reliable and power up the system;
6) Make sure the Ethernet and PoE power supply is working normal.

Another Application:

1000BASE-TX over CAT 6

1000BASE-TX over Category 6

TIA/EIA-854 : A Full Duplex Ethernet Physical Layer Specification for 1000Mb/s operating over Category 6 Balanced Twisted Pair Cabling (1000BASE-TX).

This document specifies a full duplex Ethernet physical layer interface for 1000Mb/s operation over a 100 meters of a Category 6 twisted pair cabling channel, referred to as 1000BASE-TX.

The purpose of this document, 1000BASE-TX, is to provide an Ethernet physical layer specification that is low complexity and can easily be implemented by many vendors. This will take advantage of the improved transmission parameters provided by Category 6 cabling.

It was believed by the members of this project that a much simpler solution for data rates of 1000Mb/s operating over a 100 meters of Category 6 UTP cabling would be a benefit to users who migrate to the higher data rates. It would eliminate the complicated requirements in the 1000BASE-T standard of canceling the effects of crosstalk and return loss, providing a solution that could operate at a much lower power level, the potential for multiple ports per chip, and could be implemented at a lower cost.  As it turned out, the ports became cheap very quickly and so no hardware vendor adopted this standard.

ANSI decided not to adopt TIA/EIA-854. The IEEE also decided not to adopt this and keep with 1000BASE-T as in IEEE802.3ab.

Since there is no application for this limit and it was not adopted by either ANSI or IEEE, it is not in the DTX CableAnalyzer.

Twisted Pair Cabling Connection Tips

Twisted Pair Cabling Connection Tips

 1. Recommend to use UY connectors for cable connection or soldering by parallel (as Picture.) Do not bent it for 90° (as Picture) to avoid any impendence not matching problem (Interference).

2. After cable connection, the cable joint point must be twisted back for same pair; the untwisted length must be less 10mm to avoid any interference.

3. After finish the joint cable, must be do “waterproof work” to avoid any oxidation after long time use, affect any picture quality.

4. Do not bend CAT 5 twisted pair during the cabling. To make angle less than 90° to avoid any impendence not matching problem. (Interference).

5. If your budget acceptable, then not use all 4 pairs for transmission. Leave one pairs as spare cable for any future added camera or help to resolve interference cable.

6. Do not put the remaining cable like a circle (as Picture) and not near any power box, transformers, motor, Fluorescent Lights. This way could avoid any interference caused.

Fiber media converters For Video Surveillance Cameras

As a kind of Media Converter, Fiber media converters this known as fiber transceivers or Ethernet media converters, are quite obvious networking devices those make it possible for connecting two dissimilar media types such as twisted pair Cat-5 or Cat-6 cable with fiber optic cabling. They may be essential in interconnecting fiber optic cabling-based systems with existing copper-based, structured cabling systems. Fiber ethernet media converters support many different communication protocols including Ethernet, Fast Ethernet, Gigabit Ethernet, as well as multiple cabling types such as twisted pair, multi-mode and single-mode fiber optics. Fiber media converters can connect different Local area network (LAN) media, modifying duplex and speed settings.

For video security and surveillance professionals, analog video-based CCTV systems have been the tried-and-true technology for many years. However, these same professionals are the first to recognize the migration of Ethernet into new applications beyond the typical office LAN and how Ethernet is playing a role and introducing new challenges to video security networking.

For years, Transition Networks has been talking about the benefit of fiber optic cabling and how media converters can provide a cost effective method of deploying fiber in local area networks and overcome the limitations and drawbacks of copper UTP cabling. These same benefits can be realized by security and surveillance professionals when they integrate fiber into their video networks.

For example, switching media converters can connect legacy 10BASE-T network segments to more modern 100BASE-TX or 100BASE-FX Fast Ethernet infrastructure. For instance, existing Half-Duplex hubs may be attached to 100BASE-TX Fast Ethernet network segments over 100BASE-FX fiber. When expanding the reach with the LAN to span multiple locations, fiber transceivers are useful in connecting multiple LANs to form one large campus area network that spans more than a wide geographic area.

Fiber media converters support a variety of data communication protocols including Ethernet, Fast Ethernet, Gigabit Ethernet, T1/E1/J1, DS3/E3, as well as multiple cabling types for example coax, twisted pair, multi-mode and single-mode fiber optics. Media Converter types range from small standalone devices and PC card converters to high port-density chassis systems offering many advanced features for network management.

On some devices, Simple Network Management Protocol (SNMP) enables proactive management of link status, monitoring chassis environmental statistics and sending traps to network managers in case of a fiber break or perhaps link loss on the copper port.

 

Fiber media converters can connect different Local area network (LAN) media, modifying duplex and speed settings. Switching media converters can connect legacy 10BASE-T network segments to more recent 100BASE-TX or 100BASE-FX Fast Ethernet infrastructure. For instance, existing Half-Duplex hubs can be linked to 100BASE-TX Fast Ethernet network segments over 100BASE-FX fiber.

When expanding the reach of the LAN to span multiple locations, media converters are of help in connecting multiple LANs to make one large campus area network that spans more than a limited geographic area. As premises networks are primarily copper-based, media converters can extend the reach from the LAN over single-mode fiber approximately 130 kilometers with 1550 nm optics.

The coaxial cabling utilized in analog CCTV networks suffers from transmission distance issues. The accepted distance for coax is 185 meters. While this has worked well in the past, the demands for increasing the surveillance coverage have pushed camera locations beyond the standard distances.

As for Ethernet and IP cameras, this distance is even more restrictive at 100 meters. Offering transmission over greater distances, fiber cabling is starting to play a signifigant role in surveillance networks. Fiber cabling supports transmission distances up to 2km on multimode fiber without the need for repeaters or signal boosters - with even greater distances available on single mode fiber.

Indoor applications with florescent lights, electric motors, and other sources of electromagnetic interference (EMI) along with sources of radio frequency interference (RFI) can cause disruptions and poor picture quality issues for video over Coax and UTP cabling. The transmission from cameras located outdoors is susceptible to these same conditions as well as the effect from electrical/lightening storms. Due to the nature of how data is transmitted over fiber optic cabling, it does an excellent job of blocking

this electrical interference and protecting the quality of the data.

Wavelength-division multiplexing (WDM) technology in the LAN is very beneficial in situations where fiber is at limited supply or expensive for provision. In addition to conventional dual strand fiber converters, with separate receive and transmit ports, there are also single strand fiber converters, which can extend full-duplex data transmission approximately 70 kilometers more than one optical fiber.

Other benefits of media conversion include providing a gentle migration path from copper to fiber. Fiber connections can help to eliminate electromagnetic interference. Also fiber media converters pose being a cheap solution for many who need it switches for use with fiber along with have enough money to pay for them, they can buy ordinary switches and make use of fiber media converters to make use of making use of their fiber network.

As a fiber optic media converter, you can use it anywhere in the network to integrate newer technology with existing equipment to support new applications, technologies and future growth. Fiber Converters are key aspects of Optical Networking because its long distance operation, high bandwidth capacity and reliablity make fiber optics probably the most desired channel for data communications. Instead of costly, across-the-board upgrades, media converters can extend the productive lifetime of the existing cabling along with the active equipment. FiberStore offers a wide variety of professional fiber optic media converters for Fast Ethernet, Gigabit Ethernet, Serial Datacom interfaces and E1 or T1 voice/data communications.

  

To aid in the deployment of fiber in these security and surveillance networks, Transition Networks has specifically designed a copper to fiber media converter for analog video applications. These converters are available to support both fixed-focus cameras as well as pan-tilt-zoom (PTZ) cameras. As IP cameras begin to replace analog cameras, traditional Ethernet media converters can be used for the fiber integration. Most IP cameras also support power-over-Ethernet (PoE) technology which makes installation of the cameras easier since the camera can be powered over the UTP Ethernet cable. PoE switches, PoE injectors, and PoE media converters are all available to create the functional network needed in today’s hybrid video security and surveillance applications.

Also Visit: http://arindamcctvaccesscontrol.blogspot.in/2013/12/the-role-of-fiber-in-video-networks_1043.html

How to Selecting a Video Cable

Selecting Video Cable

There are two factors that govern the selection of cable: the location of cable runs, either indoor or outdoor, and the maximum length of the individual cable runs.

Video coaxial cable is designed to transmit maximum signaling energy from a 75 ohm source to a 75 ohm load with minimum signal loss. Excessive signal loss and reflection occurs if cable rated for other than 75 ohms is used. Cable characteristics are determined by a number of factors (core material, dielectric material and shield construction, among others) and must be carefully matched to the specific application. Moreover, the transmission characteristics of the cable will be influenced by the physical environment through which the cable is run and the method of installation.

Use only high quality cable and be careful to match the cable to the environment (indoor or outdoor). Solid core, bare-copper conductor is best suited to video applications, except where flexing occurs. In locations where the cable must be continuously flexed (i.e., when used with scanners or pan & tilts), use cable intended for such movement. This cable will have a stranded wire core. Use only cable with pure copper stranding. Do not use cable with copper-plated steel stranding because it does not transmit effectively in the frequency range used in CCTV.

The preferred dielectric material is foam polyethylene. Foam polyethylene has better electrical characteristics and offers the best performance over solid polyethylene, but it is more vulnerable to moisture. Use cable with solid polyethylene dielectric in applications subject to moisture.

In the average CCTV installation, with cable lengths of less than 750 feet (228 m),RG59/U cable is a good choice. Having an outside dimension of approximately 0.25 inches, it comes in 500-and 1,000-foot rolls.

For short cable runs, use RG59/U with a 22-gauge center conductor, which has a DC resistance of about 16 ohms per 1,000 feet (304 m). For longer runs, the 20-gauge variety which has a DC resistance of approximately 10 ohms per 1,000 feet will work well. In either case, cables with polyurethane or polyethylene as the dielectric material are readily available.

For installations requiring cable runs between 800 (244 m) and 1,500 feet (457 m),RG6/U is best. Having the same electrical characteristics as RG59/U, its outer dimension also is about equal to that of RG59/U.RG6/U comes in 500-,1000-and 2000-foot rolls, and it may be obtained in a variety of dielectric and outer-jacket materials. Due to its large-diameter center conductor of about 18 gauge,RG6/ U has a DC resistance of approximately 8 ohms per 1,000 feet (304 m) and can deliver a signal farther than RG59/U.

Use RG11/U to exceed the capability of RG6/U. Once again, the electrical characteristics of this cable are basically the same as the others. The center conductor can be ordered in 14-or 18-gauge sizes, producing a DC resistance of approximately 3-8 ohms per 1,000 feet (340 m). Being the largest of the three cables at 0.405 inches, it is more difficult to handle and install.RG11/U cable usually is delivered in 500-,1000-and 2000-foot rolls.

Because of special applications, variations of RG59/U, RG6/U and RG11/U frequently are introduced by manufacturers.

Due to changes in fire and safety regulations throughout the country, Teflon and other fire-retardant materials are becoming more popular as outer-jacket and dielectric materials. In case of a fire, these materials do not give off the same poisonous fumes as PVC-type cables, and therefore, are considered safer.

For underground applications, direct burial cables, made specifically for that purpose are recommended. The outer jacket of this type of cable contains moisture-resisting and other materials that protect the cable, allowing it to be placed directly into a trench.

With numerous choices available, finding the right video cable for each camera application should be easy. After the installation has been properly assessed, read the equipment specifications and complete the appropriate calculations.

Cable Runs

coax cable has built-in losses, the longer and smaller the cable is, the more severe the losses become; and the higher the signal frequency, the more pronounced the losses. Unfortunately this is one of the most common and unnecessary problems currently plaguing CCTV security systems as a whole.

If, for example, your monitor is located 1,000 feet (304 m) from the camera, approximately 37-percent(37%) of the high frequency information will be lost in transmission. The unfortunate aspect of this condition is that it is not obvious. You cannot see information that is not there and may not even realize that information has been deleted. Because many CCTV security systems have cable runs that exceed several thousand feet, unless you are aware of this characteristic of cable, your system may be providing a seriously degraded image.

So, if your cameras and monitors are separated by lengths greater than 750 feet (228 m), you should check to make certain that some provision has been made to guarantee the video signal's transmission strength.

Cable Type* RG59/U = 750 ft.

Cable Type* RG6/U = 1,000 ft.

Cable Type* RG11/U = 1,500 ft.

* = Minimum cable requirements= 75 ohms impedance, All-copper center conductor, All-copper braided shield with 95% braid coverage.

Cable Termination

In video security systems, camera signals must travel from the camera to the monitor. The method of transmission is usually "coax" cable. Proper termination of cables is essential to a system's reliable performance.

Because the characteristic impedance of coax cable ranges from 72 to 75 ohms, it is necessary that the signal travels on a uniform path along any point in the system to prevent any picture distortion and to help ensure proper transfer of the signal from the camera to the monitor. The impedance of the cable must remain constant with a value of 75 ohms. To properly transfer power between two video devices with acceptable losses, the signal output from the camera must match the input impedance of the cable, which in turn must match the input impedance of the monitor. The end point of any video cable run must be terminated in 75 ohms. Usually, the cable run will end at the monitor, which will ensure that this requirement is met.

Usually the video input impedance of the monitor is controlled by a switch located near the looping video (input/output) connectors. This switch allows for either 75 ohm termination if the monitor is the "end point",or Hi-Z for looping to a second monitor. Check equipment specifications and instructions to determine the proper termination requirements. Failure to terminate signals properly usually results in a high contrast, slightly grainy picture. Ghosting and other signal imperfections also may be evident.

It important to note that the BNC connectors , which are usually used for terminating coax cable, are manufactured in two different impedance -75 ohm for video use and 50 ohm for radio use. Most shopkeepers are not a ware of this difference so it is better to check the manufacturer's specification before you buy.

Unsaddled twisted pair (UTP)

UTP cabling is both in expensive and ideal for transmission of video signal up to 1350m. the cabling is run to multiplexer that supports the popular RJ45 connector . Legacy cameras with coax connectors can be retrofit with balun (balanced/unbalanced ) adpters allowing the signal to be converted from the coaxial cable (unbalanced ) to twisted pair (balanced) cable. A typical system consists of a transmitter connected to a coax cable or connector which is then converted to a signal suitable for transmitting over twisted pair cable. On the receiving end of the twisted-pair cable is a receiver that converts the signal back to one suitable for transmission on coax cable.

UTP. Requires only one twisted pair cable to carry power, video and control signals , as opposed to three different proprietary cables with traditional CCTV systems.

While the total cost of UTP cabling can be up to 30% less than traditional CCTV systems over the life of the system, it easily accommodates technological advances such as digital integration IP-based networks and power over Ethernet.

Optical fibre is some times used in this environment where distances would require use of repeaters for signal strength or where EMI. (Elector-Magnetic interference) is an issue.

Fibre Optic Cable

While coaxial cable is the most suitable cable for CCTV signal transmission over short distances it is best to consider other mediums for distances greater than 1 kilometer. The most suitable for these distances is fibre optic.

Fibre optic is a fine strand of glass which is highly transparent. There are two main types referred to single mode and multi-optic fibres. The single mode fibre optic has a high level of efficiency but can transmitting only one mode. Laser transmitters an receivers arousal required for single mode application . Multi -mode fibre optics is thicker and can operate in several modes and can accommodate cheaper forms of transmission media such as infrared . These cables are used main lyover shorter distances while the single mode fibre would be used where distance and performance were critical . The main types of applications for fibre optics are:-

Light Guide fiber-used in instrument panels and lamps it carries visible light only.

Coherent fibre-Normally referred to as coherent bundle because of its construction. This glass fibre will carry an undischarged image of light over a short distance. Its ideal for extending the lens with application in covert surveillance. High performance-For CCTV application we tend to use high performance fibers with a signal transmission media. For CCTV application we have to use the latter , high performance fibers. The glass stransparency quality of the glass is a key factor in its ability to transmit light effectively over distances and this is being improved constantly.

Fiber optic system may consist of a standard camera with the video signal being fed into a fibre optic trasmitter. The transmitter consists of circuits to convert the video signal into a series of modulated pulses . These pulses are then fed to the light source that may either be a laser or light emitting diode (LED) which emits a series of light pulses .these light pulses are focused on to the centre core of the cable which acts as a guide to the light passing along the fibre's lenght. The main light passes straight along the centre of the fibre while a little of the light hits the side of the glass tube. This is reflected back into the centre by the cladding.

This results in very low transmission losses over long distances. Fibre optic cable also has the advantage of not being affected by electromagnetic interference or EMI.

Splitting / Amplifying the Video Signal

Video signal used in CCTV equipment is nominally a one volt peak-to-peak signal and is impedance sensitive to 75 ohms for ideal video reproduction at the monitor. If these parameters are not kept, then the video will degrade.

Distribution Amplification

If the installation of a system requires viewing the video at multiple locations from a single camera, there are a few different ways of accomplishing this. One way is through using a distribution amplifier. This device basically takes the single video signal and reproduces the exact signal into multiple outputs; and in the case of the Pelco DA104DT you would get four identical outputs.

So, if the input signal is a one volt peak-to-peak signal you will get four output signals of the same amplitude. Providing the run distance for the type of coax used is kept within the specified length, no other equipment will be needed to reproduce a nice clear video display on each monitor. Another timesaving feature of the Pelco DA104DT is that there are not adjustments required. Just connect the unit, turn it on, and the installation is complete. If the need arises where more than four signals are required, multiple units can be linked together by simply using one of the output signals as an input signal to the next unit, and so on.

Equalizing Amplification

Due to the many factors that can effect the video signal, it is sometimes necessary to enhance the video signal (as in transmitting a nominal video signal level) directly out of the camera, through RG59 coax to a monitor, while still producing a clear video display across the entire length of the coax. In this case the coax should not exceed 750 feet (228 m).

However, let's say you need to use RG59 because it's more flexible and much easier to work with but the cable length must be 1,500 feet (457 m). The signal at this point is going to be weak and will display a very degraded picture on the monitor. As mentioned, there are many things that can effect signal strength before the signal reaches the monitor. If you find a weak signal, simply pass the weak signal through an equalizing amplifier, make the required adjustments, and once again there will be a good, strong signal that will produce a nice picture.

The Pelco model EA2010 is a post-equalizing amplifier which simply means that this device will be located close to the monitor. There's an advantage to this design in that AC power is usually more readily available at the monitoring location than it is somewhere back up the coax line, and with this type of design it only requires one person to view the monitor display while at the same time making the required adjustments to obtain the nominal signal level.

As mentioned in the example on RG59,the signal strength is good up to nominally 750 feet (228 m). With the Pelco EA2010 amplifying the signal, the same grade of coax can be used in runs of up to 3,000 feet (914 m).

In regard to any equalizing amplification system, there is another type of post-equalizing amplifier that Pelco offers. It is the half-duplex post-equalizing amplifier. This device (as far as the amplification of the video signal is concerned) is exactly like the EA2010.The difference is that the EA2000 was designed specifically for use with any of the Pelco Coaxitron® (up-the-coax) control/transmitter systems. This device enables the video signal requiring amplification to be transmitted over the same coaxial cable over which the control signal is transmitted, whereas if you used the EA2010 it would block the Coaxitron® control signal from being transmitted.

Cabling for IP Cameras

IP convergence means attaching different building and communication systems -- such as data, voice, security cameras and building automation systems -- onto a common network through a common Internet protocol. In the surveillance world, IP convergence means moving from analog to IP cameras.

IP camera technology offers new and expanded features in CCTV surveillance that were previously unavailable on analog cameras. However, performance and scalability can be affected because of poor system infrastructure, as well as product performance.

For organizations to realize the full benefits of IP video surveillance, they must design and build a system that is capable of meeting current and future requirements, which includes allocating sufficient bandwidth to video-carrying traffic that will not congest the network. To do this, they must implement a standards-based structured cabling system that will allow future devices to be added, which will save time and money by providing the biggest return on investment.

Cable selection and bandwidth go hand-in-hand. Considerations when selecting the cable media include number of cameras, type of camera, location of the cameras (environment), distance to the telecom rooms, type of termination equipment and whether PoE will be running through the cable or local power will be provided at the device end. Another factor when selecting cable is the length of time planned to occupy the building.

Today’s TIA standards define cabling types, distances, connectors, cable system architectures, cable performance characteristics, pathways, cable installation requirements and methods of testing installed cable to help system designers and installers select the most efficient cabling for each environment. TIA-recognized structured cabling standards recommend twisted pair copper and fiber-optic cable as the preferred media selection for efficient IP network systems. However, security integrators need to be aware of the range of options available and the pros and cons of each.

Coax Cable

Distances using coax cable can be up to 3,000 feet. This cable is most often found when end users would like to use their installed cable plant, which was installed for analog cameras. However, because an IP camera is equipped with an RJ-45 connection, media converters are needed on each end of the coax cable runs.

Using existing coax cable for running Ethernet to IP cameras is a “band-aid” approach and does not comply with TIA. This is a fast solution, but eventually the cabling system will need to change to a structured cabling system -- through twisted pair or fiber -- especially when higher bandwidth megapixel cameras are required. Running Ethernet over coax is limited to less than 1 GB transmissions. Therefore, as the bandwidth increases on both the camera and the traffic running through the network, coax cable capabilities will be limited.

Twisted Pair

Unshielded or shielded twisted pair cable provides many benefits over coax. Twisted pair, with its RJ connection, allows immediate attachment to the camera. One of the biggest benefits is that twisted pair can provide power over the same cable, eliminating local power at the device end.

There are basically two grades of UTP cable: Cat-5e (100 MHz) and Cat-6 (250 MHz). A Cat-5e cable may be sufficient with its allowable 1 GB/s data rate (depending on the protocol), but Cat-6 operates at a higher data rate (up to 10 GB/s). Because of its improved transmission performance and superior immunity from external noise, systems operating over Cat-6 cabling will have fewer errors than Cat-5e. And, when inducing noise or heat -- such as in PoE and PoE Plus -- Cat-6 has been proven to operate with no latency or fear of dropped packets.

Standards-based twisted pair cabling is limited to 100 meters between the device and the termination point, such as a consolidation point or telecommunications room. The chart on the following page provides cable options for selecting cable based on distance and power. Twisted pair can actually provide a signal farther than 100 meters through active equipment, but this would not meet the TIA standards and therefore would not work if the analog camera is to be replaced with an IP camera.

Fiber-optic Cable

The answer to the distance challenge is fiber-optic cable. Fiber-optic cable can easily operate IP cameras through media conversion, allowing twisted pair patch cords or horizontal UTP cable runs to connect directly to the device and to the terminating equipment in the TR. Even coax-based analog cameras can use fiber-optic cable, but this entails deploying multiplexers in addition to media converters, which can become costly per channel.

Fiber-optic cable’s other advantages include its small diameter and biggest bandwidth carrying capacity. Fiber-optic cable is immune to electrical interference, which makes it ideal for harsh environments such as lightning, power plants and industrial manufacturing. In addition, fiber optic is a more secure signal -- because it is harder to tap into.

Since power cannot run through glass, fiber-optic cable cannot directly carry PoE. But it can be jacketed with copper conductors in the form of a composite cable. Certain cables on the market provide Ethernet to be carried through fiber strands while power runs through stranded copper conductors. Distances up to 3,850 feet can be achieved. Because the cable carries lowvoltage power -- up to 25 watts as defined by PoE Plus and IEEE 802.3at -- this cable is actually defined as a Class 3 copper cable with fiber. The total distance is limited by the media power provided through the active media converter on the termination side, as well as the gauge of the copper. The more power needed, the thicker the gauge.

Challenging Decisions and Changing Standards

Security camera locations vary depending on each installation. When the TIA standards were written, the devices in work areas consisted of telephones, modems, data terminals, fax machines and desktop computers. Although the TIA standards originally applied to data and voice Ethernet applications, mainly in office environments, they were written to be modular, providing scalability for adding IP devices. However, electronic safety and security devices, particularly surveillance equipment, create unique challenges, mainly due to environmental factors.

The BICSI organization, together with ANSI, is currently reviewing the existing standards and has created a standards group to focus solely on physical infrastructure for ESS devices. To be designated “ANSI/BICSI 005” upon completion, this standard will define cabling design and installation requirements, as well as provide recommendations specific to ESS systems, including surveillance, access control, paging, signage, and even fire detection and alarm systems.

The standard also will provide information for access control, intrusion detection and surveillance systems, as well as guidance on other topics, such as meeting the IP needs of fire detection and alarm systems. And as more and more devices find their way to the network, the selection of cabling and physical infrastructure becomes more critical.

Now we are discussed about coaxial cable's Construction

RG59/U, RG6/U and RG11/U is circular. Each has a center conductor surrounded by dielectric insulating material, which in turn is covered by a braid to shield against electromagnetic interference. The outer covering is the jacket.

The coaxial cable's two conductors are separated by a nonconductive or dielectric material. The outer conductor (braid) acts as a shield and helps isolate the center conductor from spurious electromagnetic interference. The outer covering helps physically protect the conductors.

Center Conductor:

For CCTV applications, solid copper conductors are required, which is carrying a video signal. Center conductor comes in varying diameters usually ranging from 14 gauge to 22 gauge. The structure of the center conductor generally is solid copper or copper-clad steel, designated as bare copper weld or BCW. For CCTV applications, solid copper conductors are required. Copper clad, copper weld, or BCW cables have much greater loop resistance at baseband video frequencies and should never be used for CCTV. To determine the type, look at the cut end of the center conductor. Copper clad cable will be silver in the center intead of copper all the way through. Variation in the size of the center conductor has an overall effect on the amount of DC resistance offered by cable. Cables which contain large diameter center conductors have lower resistances than cables with smaller diameters. This decreased resistance of large diameter cable enhances the ability of a cable to carry a video signal over a longer distance with better clarity, but is also more expensive and harder to work with.

For applications where the cable may move up/down or side-to-side, select cable that has a center conductor consisting of many small strands of wire. As the cable moves, these strands flex and resist wear due to fatigue better than a cable with a solid center conductor.

Dielectric Insulating Material

Center conductor is an evenly made dielectric insulating material which is available in some form of either polyurethane or polyethylene. This dielectric insulator helps determine the operating characteristics of coax cable by maintaining uniform spacing between the center conductor and its outer elements over the entire length of the cable. Dielectrics made of cellular polyurethane or foam are less likely to weaken a video signal than those made with solid polyethylene. This lower attenuation is desirable when calculating the loss/length factor of any cable. Foam also gives a cable greater flexibility, which may make an installer's job easier. Although foam dielectric material offers the best performance, it can absorb moisture, which will change its electrical behavior.

Because of its rigid properties, solid polyethylene maintains its shape better than foam and withstands the pressures of accidental pinching or crimping, but, this characteristic also makes it slightly more difficult to handle during installation. In addition, its loss/length attenuation factor is not quite as good as foam, which should be considered in long cable runs.

Braid or Shield

Cables using aluminum foil shielding or foil wrap material are not suitable for CCTV installations. Wrapped around the outside of the dielectric material is a woven copper braid (shield), which acts as a second conductor or ground connection between the camera and the monitor. It also acts as a shield against unwanted external signals commonly called electromagnetic interference or EMI, which may adversely affect a video signal.

The amount of copper or wire strands in the braid deter- mine how much EMI it keeps out. Commercial grade coax cables containing loosely woven copper braid have shielding coverages of approximately 80%. These cables are suitable for general purpose use in applications where electrical interference is known to be low. They also work well when the cable is to be installed in metal conduit or pipe, which also aids in shielding.

If you are not sure of the conditions and are not running pipe to screen out more EMI, use a cable with a "maximum shield" or heavy braid--type cable containing more copper than those of commercial grade coax. This extra copper obtains the higher shielding coverage by having more braid material made in a tighter weave. For CCTV applications, copper conductors are needed.

Cables using aluminum foil shielding or foil wrap material are not suitable for CCTV work. Instead, they usually are intended to transmit radio frequency signals such as those employed in transmitter systems or in master antenna distribution systems.

Aluminum or foil cable may distort a video signal to such a point that signal quality may be far below the level required for proper system operation, especially over long cable runs, and therefore not recommended for CCTV use.

Outer Jacket

The last component comprising a coax cable is the outer jacket. Although other materials are used, polyvinyl chloride, or PVC, is commonly used in its construction. Available in many colors such as black, white, tan, and gray, the jacket lends itself to both indoor and outdoor applications.

Newly developed some Video & Power Combination Cable is there in market.

This combination cable featuring BNC to BNC video connectors and 2.1mm DIN male & female for power supply connection. A BNC to RCA adapter is also included. Also included are two pigtails to allow breakout of power connectors to use with screw terminal power supplies and cameras. This cable is available in 50 foot and 100 foot lengths. Maximum distance for DC power should not exceed 100 feet.

Specials thanks to all of Manufacturers, Suppliers & Exporters to provide the information.

What Really Is an IP System

The market is being whipped into a frenzy by buzz about IP, yet studies show that only 10-15% of systems sold include IP cameras. What’s the deal?

One firm was recently retained by a new client to provide a strategic review on the electronic security industry. This client was focused on CCTV, and inevitably the topic of IP-based CCTV systems was high on their list. They had studied all of the market data they could find and were disappointed to discover that — depending on the estimates — only 10-15% of the systems being sold today are considered IP systems. “How can this be?” they asked. “Aren’t all systems today essentially IP based systems?”

They were right. Unless you are using a videocassette-based system or an extremely low-end DVR, all systems are IP based. Why? Because the recording is handled by a DVR, and that DVR virtually always includes client software that allows you to remotely access live or recorded video. So, if all systems are IP eventually, why is there so much discussion as to the pros and cons of IP based systems?

Close to the Edge

The real question is how far out to the edge do you go with IP. An IP system converts an analog video signal to a digital stream that can be transmitted over a conventional Ethernet network. But it can do this in a number of places.

If an IP camera is used, the signal is converted at the camera itself — this is what is commonly referred to as an IP-based system. An analog camera can also be used, and the signal can be fed into an IP encoder that converts the signal to a digital stream. The IP encoder can be located in a more convenient location, and multi-channel encoders are available to convert multiple cameras from one box. Or the camera can remain analog all the way to the recording device, which then converts the signal to store it. In that case, the recorder is also serving as an encoder, and the signal is generally available as an IP signal streaming from the recorder.

So, which system should you use? In general, we recommend that analog cameras be fed to IP encoders unless megapixel resolution is required. We base this on a number of factors, including cost, ease of installation and appearance.

1. Cost — In general, the cost of an analog camera plus an encoder is generally the same price or less than the cost of an IP camera, and technically the signal quality is identical. In fact, if multi-channel encoders are used the cost of the analog/encoder pairing drops significantly below the IP camera cost.

The true savings come in when you look at replacement cost. Edge devices fail or get damaged from time to time. One of our clients had a faulty camera installation and the outdoor IP camera filled up with water during a storm. Replacement cost was $900, but it would only have been $300 if an analog camera had been used and connected to an encoder that was safely installed in a closet or other weatherproof space.

2. Ease of Installation — An IP camera has some installation limitations that can drive costs up significantly. Primarily is cable distance — IP cameras are limited to 100 meters (328 feet) unless special converters, repeaters, or fiber optic cable is used. Analog cameras can run for great distances before being converted to IP — over a mile if the proper UTP (unshielded twisted pair) baluns are used. The same cabling can be used, so cable cost isn't an issue, and the convenience of locating equipment where conditioned space is available often outweighs other concerns.

Other installation factors include the sensitivity of IP cameras to power fluctuations, the difficulty in getting environmentally hardened IP equipment, and the limitations in size and form factor for IP base products.

Finally, analog cameras can be plugged into a portable monitor for setup, focusing, and field of view adjustments. While some IP cameras also include analog outputs to allow this, many do not. This makes installation far more difficult, involving a computer, extra network port (if power-over-Ethernet is used) and added time and complexity when installing.

3. Appearance — We are currently in the golden age of analog cameras in that the variety of sizes, shapes, features and performance levels available at low price points has never been better. This gives the designer or installer tremendous flexibility in matching cameras, housings, lens types, and other specification features to capture exactly the image that is needed. Too often, IP cameras require aesthetic or performance compromises that do not go over well with end users.

While these and other advantages make us lean in this direction, nothing trumps technical requirements. If your application makes IP cameras advantageous, feel free to mix and match or use whichever makes the most sense. As far as which type of device to use, keep both in your toolbox and remember the old adage; if the only tool you have is a hammer, pretty soon everything looks like a nail.