What is Power over Ethernet (PoE)?

What is Power over Ethernet (PoE)?

As our Professional CCTV Experience

Power over Ethernet (PoE) is a method whereby power is transmitted to Ethernet-connected equipment (VoIP telephones, WLAN transmitters, security cameras) from the central switch. By using the existing CAT-5 cabling, the need for AC power (and wiring costs) can be eliminated. The switch is also able to control power distribution to the powered devices allowing sophisticated uninterruptible power management for vital systems.

Operation

Fundamentally, a PoE load or Powered Device (PD) must fulfill three functions in order to act in conjunction with the sending end Power Sourcing Equipment (PSE). The functions are Detection, Classification, and Under-voltage Lockout.

Detection Phase

When a PoE-enabled Ethernet cable is plugged into a PD, the PSE interrogates the device to determine if it is PoE-enabled. This period is termed the detection phase. During the detection phase, the PSE applies a voltage ramp to the PD and looks for a characteristic impedance from the load (25 kO). If the correct impedance is not detected, the PSE assumes that the load is not PoE-enabled and shuts down the PoE sending end. The system then operates as a standard Ethernet connection. If the signature impedance is detected, the PSE moves on to the classification phase. The signature identification voltage is a ramp voltage between 2.5 V and 10 V. A 24.9 kO resistor provides the correct signature impedance for detection (see Figure 1).

Classification Phas
 
The PSE continues to ramp the voltage to the PD. Between 15 V and 20 V, the classification phase occurs. During this voltage transition, the PD must draw a specified current to identify the device class (see Figure 2). The simplest class (Class 0) is also implemented by the use of the 24.9 kOhm signature resistor. The classification current describes the amount of power the PD will require during normal operation. It is this information that is fed to the controller by the PSE, which allows the system to determine power budget requirements. A table of classification current and operating PD power requirements is shown in Table 1.

Turn on phase

After the classification phase, the PSE continues to ramp the input voltage up to 30 V, when the under-voltage lockout (UVLO) circuit is released and the PD is allowed to power up. Soft-start circuitry is required to limit the current drawn from the PSE. A typical under-voltage lockout circuit is shown in Figure 3.

 

By this process, the PSE and PD work together to determine the nature of the load and apply power only to PoE enabled equipment. The system controller at the central location can determine load requirements and allocate power according to an operational needs hierarchy during power failure from its available UPS budget

For additional information about driving PoE compatible load equipment and circuits for implementing Class 1 through Class 3 classification, see Design Ideas DI-70 and DI-88.

For more info please visit to www.guardtech.com.my or Call +6016-666 1221 / +6019-900 8288

The Viewing Angle of CCTV Camera Lens

The Viewing Angle of CCTV Camera Lens

Usually, at the market, we can see that the same CCTV camera we can make it at the lens of 3.6mmm, 4mm, 6mm and so on. So you may wonder what is the difference between them? How far it can “see” for the CCTV cameras? Here the “see” means we can see the objects clearly, like the car number clearly.

Here we will begin with the fixed CCTV camera lens. Obviously, the fixed lens means the focus and iris are fixed and can not to be changed.

For the 3.6mm CCTV lens, its viewing angle is 75°and can see the car number plate clearly at the distance of  2.5m.

For the 6mm lens, its viewing angle is 60° and can see the car number plate clearly at the distance of 5m.

                                              

For the 8mm lens, the viewing angle is 40° and the distance is 7m. 12mm, the 12mm lens, its viewing angle is 30° and the distance is 10m.

Of course, beasieds the fixed lens, we still have many many other kinds of lens on CCTV cameras., luje the varifocal lens, varifocal lens with auto Iris, and so on. We will talk about them at next time.

For more info please visit to www.guardtech.com.my or Call +6016-666 1221 / +6019-900 8288

CCTV Analog and IP Resolution

CCTV Resolution for Analog Cameras

Customers often ask what kind of resolution is best for their particular CCTV system. Picking the right resolution for your surveillance camera can make or break your system.

Understanding the differences between Analog and IP can go a long way in determining which equipment to purchase.

For standard analog cameras, resolution is measured by TV Lines.  For most new analog cameras the TVL range is 420 to 700.  Although 420 TVL is considered the lowest, I’ve seen camera systems where the user was only covering a short distance and the video quality was actually pretty good.  Don’t automatically assume a low res cam is garbage.  For short distances, the low resolution camera could save you some money and put a good image up.  Now, the 600 TVL and above have excellent images.  The pictures are sharper and the contrast is great.

If you want great clarity the 600+ range of resolution is the way to go.  There are other factors for a good clear picture like lenses, lux, wide dynamic range, etc.  Make sure you speak to a pro about your needs – 016 666 1221 or 019 900 8288

CCTV Resolution for DVRS (recording resolution)

Once the camera captures the images that you want, it will send them through coax cable (or Cat 5 with Baluns) to the DVR.  At the DVR, the images are converted from an analog signal into a digital format to be stored on a hard drive.  This is the most important part of the chain.  The greatest most powerful camera will not be effective if the image is compressed down to nothing by the DVR.  The two most popular DVR resolution types are CIF and D1.  CIF is defined as 320×240 pixels and D1 is 720×480.  As you can tell, D1 is 4 times larger than CIF.  That means that the raw analog signal of the camera will be compressed less, giving you better detail.

When looking for a DVR keep recording resolution in mind.  Most DVRs have both options but will usually lower the frame rate to allow for higher resolution.

CCTV Resolution for IP Cameras

Next, we’ll cover CCTV resolution for IP cameras.  IP cameras (megapixel specifically) are able to deliver a much higher resolution.  Firstly, a MP camera is already digital so there is neither conversion nor compression.  Secondly, MP cameras run their signal through Cat 5 or 6 which allows for a much higher transfer of data.

1.3M is generally the smallest resolution of IP megapixel camera, but is still quite a bit larger resolution than any analog cam.  Even though this is a huge jump from analog, if this is not enough you can jump to 3.0 megapixel and get a 2048×1536 resolution.  Still want bigger?  Go with the 5 megapixel for a 2592×1944 for a HUGH image.

If analog resolutions are not cutting it for you, IP surveillance cameras can definitely accommodate any large resolutions.

Summary

 With a DVR and analog cameras you are limited to CIF, 2CIF, 4CIF, and D1 resolution.  This may or may not fit your specific needs for your CCTV setup.  If you need higher resolution you should consider IP megapixel cameras and a network video recorder.

 

Corporate Social Responsibility (CSR) : Philanthropic Initiatives

Corporate Social Responsibility (CSR) : Philanthropic Initiatives

DNA ASIA Group strongly emphasize in giving back to the community through its various Corporate Social Responsibility (CSR) programs. Apart from being the leading Professional Closed Circuit Television (CCTV) distributor in Malaysia, we also strive to care and provide for the underprivileged in the community. DNA ASIA believes in equal human rights through non-discrimination of the gender, race and religion. As a corporate citizen, our participation mainly includes philanthropic initiatives.

We have carried out several humanitarian activities over the past few years. In one of the many successful activities, DNA ASIA Groupvisited an orphanage, Sinthamani Divine Life Ashram which is located in Jinjang Utara, Kuala Lumpur. There are approximately 31 children in the orphanage. Furthermore, there are also 4 single mothers and an old folk aged 70 plus who had taken shelter at the orphanage as their home. DNA ASIA donated CCTV appliances of various brands to the orphanage. This is to provide tight security to all the orphans living there. Not just that, the CCTV appliances would also assist the workers in the orphanage to supervise the orphans in a much easier and organized manner. Upon the donation, our ever committed and dedicated employees helped to install the CCTV appliances around the orphanage.

Our continuing pursuit is to be a socially aware and responsible global citizen towards the community. We develop strong ties with the communities in which we live and work, and focus to help propel the nation forward.

The following page will be the pictures of the orphanage visit. 

 

Rumah Kebajikan Sinthamani Divine Life Ashram is the name of the orphanage 

These were the contributions donated by DNA ASIA.

Our technicians working tirelessly to install the cctv appliances.

2012 — Year of HD-SDI CCTV Market ?

Here we show the difference between standard definition CCTV and High Definition CCTV. 

Within two years, HD-SDI has established substantial awareness in the marketplace, as tangible products materialize from an earlier TV transmission concept. Market penetration, on the other hand, has been less than stellar, due to component/ system, pricing and deliverability issues. Is 2012 really the year of HD-SDI?

HD video surveillance is an unstoppable, irreversible trend. Indeed, it is one of the few driving forces behind growth in the global security market today, according to market research.

Previously, the only means to get HD surveillance footage was via megapixel cameras and IP-based networks. Although they gave rise to new contenders and business opportunities, traditional installers have been struggling with the lack of networking and IT know-how.

HD-SDI came as a boon for “the rest of us.” With characteristics similar to analog CCTV, HD-SDI provides an alternative to IP-based video surveillance. However, other than a select few subcontracted installations in China and Korea, HD-SDI currently does not have any large-scale applications to illustrate extended usability and manageability. Most players are still focusing their energy on stabilizing overall system performance, bringing down cost and educating the market, wedging their way onto the HD video surveillance arena.

Negligible Latency

Latency has always been the Achilles' heel for IP-based video surveillance. A key advantage of HD-SDI is its real-time delivery of every frame.

Of course, this is a priority that differs in each market. For example, Chinese end users have displayed extremely high interest in HD-SDI, although they may not full understand the technology yet. "HD-SDI has a bright future in China, since some vertical markets place higher value on its low latency. This is different than other regions, where latency in video surveillance is acceptable," said Wan Yun Feng, Project Manager, Winhi.

However, latency still exists for HD-SDI, contrary to what many claim, said Zou Yu Fan, Solution Manager, Axis Communications. "It is simply relatively less noticeable. As IP-based video surveillance continues to improve at a rapid pace, latency in HD network cameras is also becoming shorter and shorter, to the point that it is now barely noticeable."

Latency is no longer a big deal-breaker for HD network cameras, Zou continued. "Compared to other technical advantages of IP-based video surveillance, latency becomes a non-issue. In contrast, HD-SDI has limited transmission distance; remote surveillance still needs to be accomplished via IP networks, which introduces additional latency."

Zhou Sheng Qiang, GM of Video Surveillance at Keda Technology, commented on HD-SDI's low latency characteristic as well. "This supposed advantage of HD-SDI's low latency over IP-based video surveillance is very small. Latency in HD network cameras is already barely noticeable, so this particular advantage over IP-based video surveillance is really not a big issue at all. In larger installations, images come from wide variety of sources, and are delivered to the video wall chiefly via IP networks. HD-SDI is more a 'last mile' solution; video still runs through the networks in real-world settings, which still requires compression. The small advantage of having low latency is not a big deal."

Indeed, as bandwidth has increased over the years, network failures and latency issues have become much less common. However, even when the naked eye fails to acknowledge the latency, a few dropped frames can be the deciding factor in whether the system is effective. End users must decide what they value the most in a video surveillance system.

No Compression…Good?

HD-SDI contenders have also touted zero image compression as a key winning point over their IP-based counterparts. Raw data is indeed delicious, just like how fresh vegies and sushi are infinitely tastier than lesser, processed foods.

However, network camera manufacturers say the lossless video is merely useful when viewing in real time, and that storage still requires the images to be compressed via HD encoders or DVRs.

Furthermore, video analytics is based on the analysis of pixels. The data still needs to be digitized and compressed for it to be processed by the analytics engine. Ultimately, the images will still be compressed.

One problem that arises is that pressure is placed on back-end devices to process all the data from every camera, added Poseidon Technology's Zeng Chun Wei. "Back-end storage and processing are HD-SDI's weaknesses."

Although lossless video sounds like a sweet deal, there are some "gotchas" to be aware of. More efficient back-end storage and processing, as well as video analytics, are common issues that HD-SDI manufacturers must resolve in the near future.

Source: a&s International | Date: 06/27/2012