Hard Knock lessons from a vet of CCTV systems large and tiny

When you’re looking at designing an IP camera system normal rules for cabling the cameras and recording the cameras go out the window. Below I have listed three design traits that have modified from traditional coaxial-based camera systems to IP based camera systems.

Rule 1 : Infrastructure Design

two years back I was presented with a big camera system that needed over 90 cameras in a building that was over 750,000 square ft. The challenge, using standard camera design, was wiring each camera back to a central location where the command console was located. In some instances, camera locations were over 1,500ft from the command center. Since coaxial cables limitation for RG59 and RG6 cable are between 800 and 1000ft, solving the distance limitation problem was critical. Using the methods available to me at the time, I had a choice between fiber optic cable or UTP ( unshielded twisted pair ) cable. Although fiber optics generally will produce a clearer picture with less distortion, it was cost prohibitive for the project. I chose UTP cable and with an active receiver at the command console and passive transmitter at the camera. This provided for wire runs of nearly 3000ft. UTP wire is just CAT3 or CAT5 cable ( frequently called Ethernet cable ), which is employed for telephone and information networks. One of the four pairs of wires sends video down the wire. The twisting of the cable provides its unique benefits. This gives the cable its name of unshielded twisted pair. At the time, now more than 4 years back, this was the best answer for the application because it met the standards for broadcasting the video and met the customer’s budget.

IP Video changes everything.

Using IP cameras presents a new set of rules for transmitting video. Where before we were able to transmit a video signal up to 1000ft using coaxial wire we are now limited to only 300ft or one hundred meters. Initially, this could seem to be a disadvantage. To anyone that is familiar with planning a computer network it is apparent that this layout is actually an advantage. Imagine the application below: You have five cameras you need installed. They’re all found along a back wall of the building looking out to the shipping and receiving area. The recorder is found at the front of the building in an IT closet. Under traditional video design, all 5 cameras would have a coaxial wire installed from the camera to the recorder. In this example, let’s say the distance is a median of 500ft from the recorder to a camera. 5 cameras at 500ft each would force 2,500ft of coaxial cable. Employing a network solution the following cabling would be required. A single cable, typically fiber, would be pulled from the front of the building to the back. At each end of the fiber, there would be a termination point. The termination point at the front of the building would be considered the Main Distribution Frame or MDF. The point at the rear of the building would be the Intermediate Distribution Frame or IDF. An IDF is outlined as a location between the MDF and the end device, in this situation the camera. All the cameras would be cabled to the IDF location. For our example, we will say it’s a median of 100ft from each camera to the IDF. We might require 500ft of network cable. Conclusion is that instead of pulling 2500ft of coaxial wire you are installing 500ft of CAT5e cable and 500ft of fiber.

The Big Bonus behind IP Video

The chief benefit behind a network solution is scalability, that leads to serious long, and short term cost savings. When you have 5 locations all with 5 cameras and all 500ft from the recorder, the costs add up quickly with traditional systems. In this scenario the cost savings can truly begin to add up. Going back to our example for a minute, we could say you need to add a new camera to view the interior shipping door. The infrastructure is already in effect. Now all that’s’s required is pulling a single CAT5e wire from the new camera location to the IDF. Perhaps this is only 50ft away. Using the old design, you would need to pull another 500ft of coaxial cable back to the recorder. This adds up to a cable savings and a big labor cost reduction.

Rule 2 : PoE – The’Power’ of a Single Cable

PoE or Power over Ethernet is simply the transmission of power along with information over a standard Ethernet wire. In a Power over Ethernet system, a PoE network switch makes available up to 15Watts of power to the end device. This could be a phonephone, camera or any other device that sits on a network and needs less than 15 watts of power. When planning an IP camera system you should look for cameras that use this technology. There are 2 basic benefits when using PoE for your system layout.

Benefit one : just one cable is critical to each camera for both power and video transmission. Vs a traditional camera system that uses a Siamese wire for both video and power. A Siamese wire has a coaxial RG59 cable and sometimes a 18 gauge two conductor wire molded together to form a single wire. This gives the appearance and straightforwardness of pulling a single cable to each camera. The flaws to Siamese cable compared to CAT5 wire is it is seriously more expressive. Siamese wires contain more copper, which is a costly commodity in today’s market. Siamese wire is also tougher and awkward to install.

Benefit 2 : No extra power supply is required for powering the cameras and it only requires a single termination at the camera and switch location. These two additional features lead to the same benefits : savings and a more flexible and scalable system solution. Scalability and space wants are becoming an enlarging concern for many IT departments. When adding a network camera system the potential rack space needed for the present as well as future can be extremely important when planning a system. Using PoE can reduce space and reduce heavy, rigid bundles of cables.

Rule 3 : Centralized or Edge Recording

There is no right or wrong when it comes to using edge recording or centralized recording. Most of your call will depend upon your particular application and existing network infrastructure. A cross-breed of the two styles may be the best solution but this could add extra cost and restrict your available camera options. In a meeting with a school district, I was asked about which solution was better. I replied that I felt neither was a better solution ; both solutions have their benefits and it relies on the application. During my meeting I described the following advantages and disadvantages of each. Centralized Recording:

Imagine you have a company that has five buildings ranging in size between ten thousand to fifty thousand square ft. All 5 of your buildings are located within a large industrial park. Each building has a restricted number of fiber optic cables between them. Your company has a main server room found in the largest of the five buildings. The IT department manages the server room and there’s limited prohibited access to that room. The remaining 4 buildings are accessible via fiber from the server room.

For this example, centralized recording offers you the most inexpensive and scalable solution. Centralized recording works well here. There’s a main server room and all of the buildings are connected through locally owned fiber. Using a single recording location is cheap because all the recorded video is stored at a central location. A single server as opposed to 5 servers ( if using edge recording ) will record the video, leading to a significant cost savings. In each building, PoE network switches would connect to the cameras. The fiber optic wire would broadcast the video back to the central server room for recording. This solution is also very scalable. Adding a camera to any location within the five buildings is as simple as connecting a camera to the nearest PoE switch. In this particular application, centralized recording fits best thanks to the environment and infrastructure available. A disadvantage of centralized recording is if a fiber is cut between any one of the buildings and the server, all of the cameras inside that building will no longer be recorded or be able to be viewed live. In this example, all the video from these cameras will be lost.

Edge Recording:

In this example, you’ve a company office building and a producing plant. The 2 buildings are found about one mile except for one another. You’ve a dedicated T1 connection between the 2 locations. The T1 is used to share data transmission between the two sites. Most of the installed cameras will be at the producing plant so that company is ready to monitor the plant remotely. The corporate office will have four to 6 cameras installed to view the main entrance and worker parking area.

For this example, edge recording offers the most inexpensive answer for your company. Limited connectivity between the two locations is the biggest obstruction. The standard IP camera requires about 2Mb per second available bandwidth. The first camera would consume all of the available bandwidth of a T1 connection making centralized recording very unlikely. Edge recording does not stop centralized viewing it only prevents the recording of the camera centrally. For this example, you would use 2 network video recorders. You would scale each recorder to fit the quantity of cameras they will be recording. From the client side or remote connection, you would be able to configure the system as though it were a single connection. The sole difference would be the refresh speed of the remote cameras. In this example, edge recording provides the most cheap answer while still meeting the goals of your company. The downside, in this application, is the price of having 2 servers and slower live display rates of the cameras.

The Rule Summary:

By reading this, i hope that you are able to see how IP video offers a completely different design and new features that were not possible or cost prohibitive with a traditional coaxial cable system. There are countless other benefits when using IP video. The three mentioned above are only some of the advantages that IP video technology has provided to the safety industry.

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