Showing posts with label PoE. Show all posts
Showing posts with label PoE. Show all posts

Friday, August 14, 2015

Installation of Camera In Harsh Environment

In this article, our aim to provide you some basic information about same standard which determine the outdoor working reliability. Outdoor Security cameras must be able to continue working properly. To achieve this, the security cameras must can effectively withstand in harsh conditions - such as rain, dust, wind, sand, salt, extreme hot and cold temperature etc. Many factors determine the camera whether they are suitable for specific outdoor critical environments.

1.       WEATHERPROOF STANDARD - INGRESS PROTECTION (IP)
To let user know whether certain products are suitable for certain conditions, some international organizations set standards that can indicate how effectively product can work in environment prone to water, dust, explosion and impact. Ingress protection is the most widely used one standard.


IP stands for ingress protection which is a standard (IEC-529) that specify how caable equipment can withstand the ingress, or entry, of dust or water. An IP is usually consisted of two numerals, the first digital indicates the level of protection that the enclosure provides against access to hazardous parts (e.g. electrical conductors, moving parts) and the ingress of solid foreign objects, the second digital indicates the protection of the equipment inside the enclosure against harmful ingress of water. For harsh environment, the security camera should be rated IP66 to IP68 as opposed to IP32 to IP54 for indoor environment.

2.       IMPACT PROTECTION - IK RATING
IK or impact protection, is the standard that specify degrees of protection provided by enclosures for electrical equipment against external mechanical impacts in accordance with IEC 62262:2002 and IEC 60068-2-75:1997. IK rating system ranges from IK00, or no protection, to IK10, or protection against 20 joules impact, equivalent to impact of 5kg mass dropped from 400 mm above impacted surface. Typically, vandal-proof security cameras utilizes high impact polycarbonate plastic dome. Tamper-resistant screws make the unit resistant to vandalism.

3.       SURGE PROTECTION
The majority of all surge-induced damage is caused by surges and spikes travelling along unprotected video, data, and power lines. These surges originally come from a wide variety of sources, including lightning strikes and static charge buildup. Surge protection can provide protection for both IP video surveillance and analog video surveillance systems which include front-end cameras, data lines, power lines, back-end storage DVR, NVR, as well as PoE switches. When security cameras are installed outdoor, extra surge protection is essential, surge protection is a smart investment in preventing not only equipment loss, but the potential loss of critical information.

4.       EXTREME LOW/HIGH TEMPERATURE
Users also need to consider the temperature factor if the camera is installed in extreme hot or low temperature degrees environment, the security cameras should be able to withstand these conditions. While typical security camera ought to have a working temperature range from -10 to 60 degrees Celsius, critical environment products should be able to work in a range between -40 and 70 degrees Celsius. Some IP cameras has built-in heater and fan to maintain the camera's inner temperature therefore allows camera to work in an extreme high/low environments.

5.       OTHER CUTTING-EDGE TECHNOLOGIES
Many other new technologies which has been implemented into security camera to enable them work in places that subject to danger or extreme weather conditions. Pelco by Scheider Electric released a series of products that have capability to withstand water and dust ingress, fog, high and low temperatures, winds of up to 57 meters per second, explosions, and corrosion by salt and different types of chemicals.

Many different technologies have been utilized to make those features possible. For example, some products feature the pressurized integrated optics cartridge (IOC) technology, which is able to protect the equipment from moisture and airborne contaminants and packages an auto-focus camera, lens, heater, and sensors in a small, self-contained, and sealed unit. Another cutting-edge technology is Dry nitrogen pressurized to 10 pounds per square inch gauge (PSIG), which protects the environment inside the cartridge, whereby sensors strategically placed in the cartridge send an alert message if changes in pressure, humidity, or temperature are beyond factory-set threshold points.

Some security cameras also feature heater, window defroster, sun shroud, and thermal insulation blanket to enable operation in temperature conditions ranging from as low as -46 degrees Celsius to over 49. In case the power failure during an ice store, the entire camera can deice itself and become operational in just two hours after power restore at a temperature as as -25 degrees Celsius.

Sunday, March 15, 2015

Power Over Ethernet - Way to Go

Power Over Ethernet May Be The Way to Go
Power over Ethernet (PoE) is a technology that powers a remote Ethernet device by transferring electrical power over the same standard twisted-pair Ethernet cable that used to also send Ethernet data communication.
Here are some benefits to using PoE:

Simple – A single cable can supply power and network connection
Space – Only one set of wires to deal with saves space and simplifies installation
Maintenance – Easier to deal with low voltage issues
Easy –Very easy install cameras and extend your network
Reach – Supports longer camera runs with Ethernet cable (ft.)
Savings – Cost savings on many levels (installs, labor, etc)
Look into Power over Ethernet injectors or switches to assist you in transmitting electrical power, along with data, to remote devices over your network. The benefits could be endless!

There are two main types of PoE, active and passive.

  1. Active PoE is standardized by the IEEE 802.3af (PoE) and 802.3at (PoE+ which provides more power). Active PoE requires negotiation between the device and the power source. Double check if this matters, but I am pretty sure this is supported to the supported length of cable for ethernet of the particular type (100Mbps or gigabit). Active PoE is mostly the domain of enterprise stuff. It's not generally inexpensive. In general[1] you can plug a non 802.3af/at PoE device in to network port that has power being provided to on that standard and all will be fine.
  2. Typical Application

  3. Passive PoE is simplistic and simply uses a pair of the 8 wires in an ethernet cable for running power. How much power this can provide and how far the device can be from the power source varies wildly. There are some "standards" but they are by convention rather than formalized. It's generally bad (tm) to plug a device that is not expecting passive PoE in to a port that is powered as such. If you have a well designed network device, it might not fry the device, but it really shouldn't work.
In standard cat-5 cabling for 10Mbit or 100Mbit Ethernet only 4 of the 8 wires are actually used.
Power over Ethernet is a technique to use the unused pairs: (4,5 and 8,7) to carry DC power to the device.
Some devices contain the circuitry to actually be powered directly; in other cases you need to split the power off the Ethernet cabling and feed it into the equipment the normal way.
Intel, Ayaya, Orinoco, Wavelan, 3Com and Symbol use 4,5 = ground and 7,8 is positive
Cisco aironet use 7,8 = ground, 4,5 = positive.
RJ45 Pin #
Wire Color
10Base-T Signal
PoE
(T568A)
100Base-TX Signal
1
White/Green
Transmit (+)
Mode A +
2
Green
Transmit (-)
Mode A +
3
White/ Orange
Receive (+)
Mode A -
4
Blue
Unused
Mode B +
5
White/ Blue
Unused
Mode B +
6
Orange
Receive (-)
Mode A -
7
White/ Brown
Unused
Mode B -
8
Brown
Unused
Mode B -
Power over Ethernet Pinout
Same As The Straight-Through Cable Pinout for T568A
It eliminates the need for power outlets at the camera locations and enables easier application of uninterruptible power supplies (UPS) to ensure 24 hours a day, 7 days a week operation.

PoE technology is regulated in a standard called IEEE 802.3af and is designed in a way that does not degrade the network data communication performance or decrease the network reach. The power delivered over the LAN infrastructure is automatically activated when a compatible terminal is identified, and blocked to legacy devices that are not compatible. This feature allows users to freely and safely mix legacy and PoE-compatible devices, on their network.

The standard provides power up to 15.4W on the switch or midspan side, which translates to a maximum power consumption of 12.9W on the device/camera side - making it suitable for indoor cameras. Outdoor cameras as well as PTZ and dome cameras have a power consumption that normally exceeds this, making PoE functionality less suitable. Some manufacturers also offer non-standard proprietary products providing suitable power for these applications as well,but it should be noted that since these are non-standard products, no interoperability between different brands is possible. The 802.3af standard also provides support for so-called power classification, which allows for a negotiation of power consumption between the PoE unit and the devices. This means an intelligent switch can reserve sufficient, and not superfluous, power for the device (camera) - with the possible result that the switch could enable more PoE outputs.

Sunday, February 1, 2015

Seven Advantages of IP or Network Camera Surveillance System

Seven Advantages of IP / Network Camera Surveillance System

1, the advancement: system use existing integrated wiring network transmission of images, and real-time surveillance. The system front-end equipment, attachment is concise, the back-end and only a set of software system.

2, reliability: the main equipment of WDR PoE network IP camera adopted embedded real-time operating system, the required equipment is simple, and image transmission is implemented through integrated wiring network, the reliability of the system is high.

3, price performance ratio: the required equipment system is extremely simple, system control by the backend software system implementation, eliminating the traditional analog surveillance system of a large number of devices, as a result of the image transmission through the network integrated wiring, saves a lot of video coaxial cable, reducing the cost.

4, security: system set up different levels of user permissions, only the highest authority of the user to set or change to the whole system, without permission of the user is receiving less than the image.

5, easy maintenance: the 3 megapixel waterproof IR h.264 CMOS IP camera installation of the system is simple, installation and use of the software system is also very simple. In the aspect of maintenance, system wiring is very simple, and the reliability of the main equipment is very high, maintain good performance, and can realize remote maintenance.

6, easy extension: when the need to increase surveillance points, surveillance host, only need to add 3MP outdoor vandalproof HD wdr dome camera can be through the existing network, without the need to change existing wiring system what to do.

7, wide range of application: using the network transmit real-time image, such as office, building inter-district remote surveillance: chain business, large factory room, the distal child care for the elderly, public building, there is no dangerous environment surveillance, surveillance, traffic regulation of all financial institutions branch, false alarms distinguishing, etc.

Saturday, June 21, 2014

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.

Thursday, March 14, 2013

Guarding against theft using Outdoor IP Camera



Are you ever have the experience of worried about strangers knocking at your door when your child at home alone? May be every parents have this kind of feeling. Needless to say, that is really a dangerous situation when adults were not at home. Thief or evil guy may take the chance of using children’s innocent resorts to all means in order to achieve his goal. How can we parents to avoid the same thing happen again? We would like to introduce Outdoor IP Camera. The best life and property guarder of your family.

Network Attached Outdoor IP Cameras and Wireless IP Camera attach to the network just like a computer. Set the IP address and they can be viewed by a web browser. Add powerful IP software and you can create a sophisticated surveillance system. Outdoor IP Cameras are much easier to install then the older analog CCTV cameras. The cameras are all connected to the network using standard network cable. The latest cameras can even be powered over Ethernet (POE), making installation even simpler. The new outdoor IP cameras from Axis are powered by POE.
Our complete Outdoor IP Camera systems for indoor or outdoor applications include Outdoor IP cameras, servers, storage, enclosures, lenses and software; everything you need to create a working surveillance system.

That sounds simple enough but when you’re trying to choose the right Outdoor IP camera you’ll begin to notice how many different types of cameras there are:
Weatherproof IP Cameras
Wireless IP Cameras
Indoor IP Cameras / Outdoor IP Cameras


That list can be even further segmented but you get the idea. It can be a dizzying process to wade through the available choices. But, there’s a reason for all the options and in our ongoing discussion of how to find the right Outdoor IP Camera for your project I’ll be detailing the camera types and how/where they are used.

Do you have a clear mind about Outdoor IP Camera, if not, buying one and supplying a more security environment for your children .

Saturday, January 26, 2013

How fiber optic cabling combined 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) / Speed Dome Camera capabilities, and weather-hardened cameras used in cold environments that feature blowers and de-icers.

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.

Sunday, November 18, 2012

Understanding Power over Ethernet for video surveillance

PoE was, and is, supposed to make the powering of devices easy. You take your camera or other device that accepts power via the Ethernet port, you plug in the RJ45 jack to the port, and you walk away. Inside the head end, you plug the other end of the same Ethernet cable into a PoE switch or PoE injector and voila, power is magically delivered to the device along with the data connection. In theory, all of the normal worries are gone. AC power or DC power is irrelevant, and you don't even have to worry about over-powering a camera that, were you to fry it, could potentially set you back a few thousand dollars in equipment costs and man hours!
PoE was supposed to be this way, but practical reality has diverged from the perfect world concept in such a way that the actual installation is almost never that easy. So set aside the “perfect world” notions you have, and let’s start with the basics, so you can understand how PoE works.
There are four classes of PoE: Class 1, 2, 3 and 0. Each PoE classification denotes a range of power that is available to the end device as well as the power that must be available on the port of the power sourcing equipment (PSE):
PoE Classifications
  • Class 1 --  4.5 watts at PoE port; 3.84 watts at device
  • Class 2 --  7.5 watts at PoE port; 6.49 watts at device
  • Class 3 --  15.4 watts at PoE port; 12.95 watts at device
  • Class 0 --  15.4 watts at PoE port; .44 to 12.95 watts at device
In the world of PoE there are two kinds of switches that can provide PoE; the kind that operates with a “guarantee per port” and the kind that operates with a “total power budget”. Both kinds of switching are useful but there is a significant difference between them. If you happen to have a switch nearby, look at it and see if you can tell into which one of the above two categories your switch falls.
A switch that guarantees a certain wattage per port -- 15.4 watts per port, for example -- means that you can be sure that no matter how many Class 3 or Class 0 devices are plugged in, the switch will be able to power them. Of course, these switches tend to be bigger, more expensive and ill-suited for use outside of a nice climate controlled room, but they do prevent errors in power planning.
The second type of switch mentioned above -- the kind with a total power budget -- can only power as many PoE devices as it has power to spare. Imagine that you are working with a 4-port switch that carries a total power budget of 30 watts. This kind of switch could power four Class 2 cameras (4 devices x 7.5 watts = 30 watts needed). It could also easily power four Class 1 devices (4 devices x 4.5 watts = 18 watts needed). Continuing with that math, it would be able to power Class 3 or Class 0 devices, but it could only power two of those types of devices.
Power planning is where the rubber meets the road, and it brings up a challenge in our industry.
What happens if a chosen device (i.e., a PoE powered camera) does not clearly specify the PoE class and instead simply gives an operating wattage? You might think that this is OK since a camera which says “6.01 watts” is within the Class 2 specifications and therefore must be Class 2. But that’s where reality often diverges from common sense. In theory, what is supposed to happen is that a device is clearly labeled with a PoE classification so that when said device is plugged into a PSE device, the power budget has been worked out such that each device will receive its required PoE.
What I believe the security industry needs – right now, since PoE is happening today -- is clear labeling of the correct classification of PoE on each and every device that uses PoE. It is all well and good to place the operating or maximum wattage on the device, but industry manufacturers need to take the next step!
Manufacturers should label the device, print it on in large type and with bold colors, CLASS 1, CLASS 2, CLASS 3, CLASS 0, or whatever PoE Plus will hold as a classification. It's OK if your device actually only draws 3 watts during normal operation but for some reason is Class 0. Just tell your integrator channel partners and end users by labeling the device in the manner in which it was intended to be used. This lets system designers know the classification so that they might properly create a power plan and buy the correct devices. No one wants to be in the field trying to get a project done on time and only then realize that their switches don’t have enough power for the devices they’ve purchased.
While I am solidly standing on my PoE soapbox, let me also make a plea for PoE classification to be a priority on data sheets and marketing slicks. Some camera manufacturers make wonderful versions of these spec sheets. You’ll find photos, technical illustrations, cross reference charts, and more -- and often not a hint of PoE classification to be found anywhere. As someone who works with PoE, it sometimes seems as though PoE has become the crazy uncle that everyone has and who no one wants to invite to the party. Unfortunately for all of us, the crazy uncle could actually be the life of the party -- he makes it easy to entertain the guests and always has enough cash to pay for pizza -- but we haven't managed to take advantage of him yet!
PoE is supposed to make things easy, and between the standards bodies, the independent PoE offerings, the lack of classification usage, the errors in PoE chip usage within devices, and the propensity of some manufacturers to create Class 0 signatures in devices that draw minimal wattage, PoE's original purpose has been obfuscated in a way only rivaled by the current explanation of the financial bailout.

Why has it become so complex? Who knows! Unfortunately it has, and confusion has also shared a taxi with a lack of education on the road to PoE's widespread acceptance. People see a label on a device that says “802.af” or “IEEE Compliant” and then automatically assume that they can plug it into a PoE switch or midpsan and have it work with no problem. What makes the education problem worse is that often it does work with no problem, and this leads people to the assumption that PoE is really nothing more than Windows “plug and play” for power. Unlike Windows, however, there is no “blue screen of death” when using PoE. Instead there is a device that does not power on, or (in rare cases) a device that does power on followed by smoke, the smell of singed chip boards and fried capacitors, and then what was a very expensive security device becomes an equally expensive paperweight.

Friday, December 31, 2010

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.