Advantages of digital technology
• A higher resolution may be possible, depending on the product, which allows details that will be recognized more easily.
• The digital zoom is possible using mega-pixel camera.
• Normally, IP cameras can be easily configured during installation, through browsers or software.
• The subsequent expansion of the camera system and the single chamber can be performed using fully digital system solutions.
• You have less noise (video and control) in the lines for digital transmission of signals.
• If the system is small, you can use the existing network (after prior verification) without causing any damage to the performance when operating the hardware and software within the network.
• Live images or file may be available to all users with appropriate access rights within the network on their workstations.
• In the digital system solutions, the video storage capacity depends only on the size of hard disks or on the server.
Disadvantages of digital technology
• Currently, most IP cameras are less than the cameras with respect to light sensitivity, color fidelity light low, dynamics and resolution (if the camera is a camera mega-pixels).
• The frame rates of the mega-pixel cameras that have to transfer and store frames with higher resolutions, generally can not be achieved in real time due to a significant increase in the volume of data.
• The selection of appropriate lenses for megapixel cameras, it is still very limited. It takes time for all current zoom lenses available for the use of mega-pixels.
• IP cameras from different manufacturers are not compatible. This means that if you want to do a replacement of major technical components (eg HDVR, NVR) or video management software (say after a period of two years), is much more difficult than using analog cameras that work with PAL signal standard (hence, are compatible with each other).
• Due to the lack of compatibility, IP cameras to be integrated in a hardware / software platforms from multiple vendors. For system design, this usually results in a limitation in function during the integration process, as all the technical features of the IP camera can not always be integrated into these different platforms.
• Particularly when it comes to image compression method of movement completed (eg H26x, MPEG-2, MPEG-4), there is usually extremely high latency when operating head pan / tilt and high-speed domes.
• The costs of data protection are also much higher than when using conventional analog technology (especially when using existing networks and computers). In addition to the configuration of video devices themselves, calculate time and extra administrative costs for the network configuration of routers, switches, repeaters, servers, etc.
aspects to consider when installing
With the use of transmission of analog video signals and cable, the transmission rates up to 300 meters can be achieved using a single 75-ohm coaxial cable (0.6/3.7), without any intermediate amplification.
When transmitting digital video signals within the local, intermediate amplification is required after 100 meters, the intermediate amplification within the network area is usually done using traditional components such as switches or repeaters. During the planning phase and configuration, the cost of these components plays an important role, especially when it requires new wiring. If the cable connections on the network to the external cameras are greater than 100 meters, is something to be taken into account. Understandably, the use of internal network lines in outer areas is risky and requires additional protective measures, even if the network in question is an independent video network. In most cases, argue that digital technology usually completely forgotten to mention the costs involved in signal amplification and additional security measures.
Some IP cameras have been integrated supply modules PoE (Power over Ethernet), this ensures you get the IP camera line power from the existing network. The advantage is clear: No separate power supply required, however, depending on the power consumption of IP camera limits the number of cameras can be installed hears two switches using integrated PoE function.
addition, wiring is required for star distribution network cameras. In addition, when using external cameras, PoE function can not be used because of the large distances to be commercial cubrirse.Aspectos Due to the use of intranets, many companies assign their own IT departments planning and acquisition of video monitoring equipment. In the past, when using conventional analog technology, the maintenance department was usually assigned to this task.
The fact that IT budgets are usually much higher than comparable estimates for maintenance, tend to encourage the use of digital technology.
If we believe in marketing promotions and reports of many product catalogs, then the user simply use modern technology digital, and it alone, as is the current trend.
What is Power over Ethernet?
Power over Ethernet (PoE) ) also known as Power Over LAN (PoL) is analogous to the DC power provided by the phone system Traditional, except that the energy continues to use the same CAT5 cable Ethernet data. The Institute of Electrical and Electronic Engineers (IEEE) developed the IEEE 802.3af standard which many vendors base their PoE products. IEEE 802at is a new standard currently under review, which is known as "PoE".
How does Power Over Ethernet?
CAT5 PoE begins by using a "nozzle" that injects the DC voltage. in the cable. The voltage is typically 48 volts. On the receiving end, the CAT 5 cable can result in a "Picker DC or Tap" or "Ethernet Splitter" which raises the DC voltage to a DC power stroke. There are also compatible devices "PoE" that get their power directly from the CAT5 cable CC. PoE is fully compatible with other Ethernet protocols.
What are the advantages of Power over Ethernet?
Some of the benefits of PoE are:
1. BajoPoE a cost eliminates the need to manage power cables and data to each device or the network d separately. The cost of installation n is reduced because you do not need a licensed electrician to wire AC power to each device o.
2. FlexibilidadLos devices network can be established regardless of sources of AC power at locations that are difficult to reach with AC power.
3. ConfiabilidadPoE can run power sources (UPS) to allow network devices work even during blackouts. VOIPSA phones can do almost as reliable as conventional phones.
4. Administration and management PoE devices can be managed using Simple Network Management Protocol (SNMP).
then prove the content of such marketing statements (1-5) and put them in total technical context, illustrating both the advantages and disadvantages:
1. mega-pixel cameras have higher resolution 
IP cameras using image sensors mega-pixel really does have higher resolution (and therefore offer details more clearly structured) an analog CCD camera which is limited to a maximum of 440,000 pixels (due to the PAL standard). Therefore, it is possible to make a digital zoom, through which a portion of the image is about the framework, however, the higher the pixel count, the lower the corresponding pixel, and the camera loses sensitivity proportionally light, this means that under certain circumstances will have to work harder and involve more costs to achieve enlightenment within the area to be monitored.
Tip: Under identical conditions, compare an analog camera with a digital camera mega-pixels directly within the object being monitored. Pay close attention to the light sensitivity and color fidelity, especially when lighting conditions are poor.
Member only benefits from a camera with megapixel resolution where such high resolution is simply not "lost" because the additional components are connected down to the respective transmission or recording. A good example of this is when a VGA resolution must be converted to MPEG for performance reasons. Therefore, you should ensure that both the lens and the video and recording devices that have connected support the high resolution of the camera.
2. progressive record is "better than the record under" PAL The method is based on analog cameras 50 fields per second, which is then interlaced at 25 frames per second (fps). Because the 50 fields are displayed in a row (a compensation of 20 milliseconds per frame), fast movements can produce a motion effect, making the monitor still image is not clear, then presents this image blur when is stored or printed. With digital cameras are not generated fields.
Instead, you get full frame images and non-interlaced, this is called progressive record. However, in all marketing promotions digital enthusiast usually forgets to mention that professional analog cameras are already equipped with electronic shutter function for almost 20 years, allowing them to submit even the fastest movements with extreme clarity and sharpness. Tip: If you need to detect fast moving objects within the object being monitored, then leave the definition displayed on the monitor both live image to image file.
Here are some examples of how to display different IP camera models (TRENDNET)
3. IP Cameras offer better quality: The quality of an image is the result of a combination of different technical factors. Among them we can talk about resolution, color rendition, light sensitivity, contrast, brightness, dynamic (when there is black light), depth of focus, etc, from the above, this general statement is not correct. In particular, IP cameras offered by manufacturers outside the CCTV industry, usually are much lower than analog cameras, especially in these disciplines.
way, a webcam that costs $ 19, also is an IP camera.
Tip: In the object being monitored, compare an analog camera with IP camera and insist that he displayed the advantages. Ultimately, you are the person who decides if the image quality of an IP camera is actually better or not. And do not forget: cameras should also be able to provide acceptable images at night under low light or artificial light.
4. IP cameras can be easily integrated into existing networks :
This statement is true when the administrator responsible for the system first has solved all the problems around the issues of "safety net" and "charges the network. " If video systems are already built into the network, then it is relatively easy to increase the number of cameras. Be careful when you hear that "the locations of the cameras can be installed or easily changed by simply connecting the camera to a wall outlet or unplugging it." This statement is true only when the lines of the network and the same outlets have been installed in all planned locations of the inner chambers (usually in the corner of the room at ceiling height). Tip: Include from the principle to solve hold-planning system based on video monitoring network.
5. digital systems, installed more easily and cheaply : This version is correct only when the number of IP cameras is so limited that the existing network does not suffer disturbances or even failed due to its inherent limitation of bandwidth after the extra load is added from the video monitoring equipment. However, if you plan to use many IP cameras, then, for security reasons, you should also plan a separate network exclusively for video application. If you have to completely rewire this reason, then the digital systems are no longer easy and less costly to install. If separate network lines and the 75 Ohm coaxial cable have not yet been installed at the planned location of the cameras, then you can also transmit the analog video signals, using video transmitters and receivers of two wires and low prices on existing telephone wires, where we can find pairs of wires still unassigned.
Tip: The higher the image quality you need, the greater the burden of network video monitoring equipment. But you can significantly reduce the load on the network using analog cameras, if they are incorporated into the local network via a digital (DVR). If you are using the compression method conditional DVR with network load adjustable, so in many cases you can integrate video surveillance systems to larger networks. All users with access rights can then access all cameras for live pictures or file from your computer, even when using analog cameras.
Summary
Depending on the application and the reasons that have to monitor for video, the technology to be used should be analyzed carefully, and focused on specific user requirements. Many operators have invested in video surveillance technology in the last 20 years. If one considers that in the past, in Germany alone, many hundreds of thousands of analog cameras had been installed, you can quickly reach the conclusion that there are to plan and install systems that support intelligent and efficient both analog camera technology modern technology such as IP camera.
Just for this reason, manufacturers have been working in the field of security technology for a long time, have system components developed according to specifications, which optimally combines the best of both worlds. Modern hybrid systems for recording and transmitting optimally exploit the advantages of both technologies to benefit the client. By the way, even in other fields of industry, experts are of the opinion that it is the combination of the new digital world with the old analog world (tubes), that really delivers the benefits to customers. Even today in Germany, the analog camera technology is being used in more than 90% of cases.
therefore assume that the proportion of digital video components will increase dramatically in coming years. The "death" of the analog camera technology within the next five to ten years, as has been predicted by some experts, is something that simply can not see. Users interested in video monitoring should take the time to find the camera technology to achieve optimum camera locations for each task you have on hand. If these users, with all their individual requirements, change to a security company that has a proven track record with both technologies, then the result will surely be for the benefit of customers.
* Michael Meissner, is managing director of Digital Video HeiTel GMBH.
