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VIDEO SURVEILLANCE - Watching with Ethernet
The price of Internet-connected video devices (webcams) is falling rapidly while their overall 
features and reliability are rising. As the demand for video surveillance increases, many enterprises are looking at ways to use webcams for that purpose. Justin Bewick explains why webcams are a suitable solution for modern surveillance needs, and argues how deployment of 802.3af Power over Ethernet (PoE) in combination with high-quality structured cabling can optimise their use
With the cost of employing security personnel increasing, video surveillance is becoming an ever more vital tool in maintaining security of business premises and people or material within them. Video surveillance is also an important tool for intruder detection and identification of unauthorized activities by employees, contractors and visitors. In combination with other security measures such as intercoms and electronic door locks, it can provide secure access to restricted areas, ensuring that only authorized personnel are admitted.
Video surveillance is not just useful from a security point of view. It can also be used as part of the environmental management of the building, switching on (and off) lighting and heating and verifying that doors, windows, etc. are shut. Likewise, it may be used for safety reasons, detecting, for example, whether lifts are occupied or not.
The key to all these diverse video surveillance applications is price and ease of deployment. Webcams, that is to say video devices connected to the enterprise's IP data network, are ideal in this respect as they are generally significantly cheaper and easier to deploy and move.
Their main drawback - one often shared by traditional CCTV devices - is that they require a separate power supply in addition to the data cable, which in turn means that positioning depends on the ability to connect to the building's power. That problem is made worse by the fact that many webcams have a separate mini transformer that must be plugged in.
Traditional CCTV systems require connection to a dedicated cable, generally coax. Not only does the requirement for a dedicated wiring network conflict with standard cable management practices such as structured cabling, but coaxial cable is no longer in common use and is typically some 30-40 per cent more expensive.
On the other hand, a webcam just needs a standard Ethernet cable, no matter whether UTP or screened to provide environmental protection, something that is usually readily available or need merely be pulled to the nearest wiring closet. Using a webcam solution allows for a non-proprietary, open solution. The installation is not dependant on one vendor and it is simple mixing and matching equipment from different vendors. Replacing a failed camera whose supplier is no longer in business or no longer supports it is a straightforward matter.
Coax may seem to have an advantage over UTP in exterior locations and other harsh environments, but in today's market there are ways to make Ethernet networks just as environmentally resistant. Reichle & De-Massari offers an industrial cabling solution with Insulation Displacement Contact (IDC) technology, which includes RJ45 connectors and connection modules that are sealed, gas- and water-tight and vibration resistant.
With these considerations in mind, it is clear that proper network planning and use of standards-compliant structured cabling must be applied. The optimal approach is an identifiable separate network for security. Ideally this will use entirely separate active equipment and wiring, both copper and fibre, however by implementing a separate VLAN on an existing network infrastructure the same level of security may be reached.
Power over Ethernet
The issue of power supply is relevant to all video surveillance equipment. No matter what the system, every device needs to have both electrical power and some sort of data feed. Supplying power to video equipment can be difficult because cameras are frequently placed well away from the main power runs and sockets.
However where webcams use Power over Ethernet, they can receive both data and power from a single cable. Power over Ethernet (PoE) has been standardized as IEEE 802.3af. The standard is robust and failsafe, enabling a number of possible approaches to adding power to the standard UTP or shielded (SF-UTP) Ethernet cable run, and specifying that the devices drawing power from the cable should support all methods.
The power provided is a maximum of 350mA at 48V (802.3af) which, after taking cable losses into consideration, means that the end device must consume no more than 15W. This is not enough to power a personal computer, but is more than enough for an IP phone or a webcam.
PoE also neatly solves the need for security surveillance to be operational even if the building has lost power. Unless the supply of electricity to the entire building is backed up by UPS, traditional CCTV will stop working. A PoE solution, by contrast, relies on an infrastructure that in most enterprises already has UPS, namely the corporate data network.
Ethernet data networks using structured cabling and distribution schemes gain hugely from the flexibility and manageability these techniques offer. In the case of video surveillance structured cabling greatly ease network alterations. However, this flexibility comes at a price: making it easy for people to tamper with the system, whether accidentally or with intent.
R&M's Patch Guard system, for instance, offers lockable patch cables and panels. It is ideal for server rooms and also very suitable for webcam security, making accidental tampering less likely, and malicious tampering both harder and significantly more obvious.
Another potential benefit of structured wiring is that it makes it comparatively easy to create a resilient network that can survive equipment outages or cable cuts. Clearly an individual webcam will be lost if the cable to it fails, but between the wiring closets and the security control centre the use of redundant paths to ensure reliability is entirely standard. This means that the overall reliability of a PoE webcam solution is likely to be greater than that of a traditional solution.
Future proof
To be future proof, your surveillance solution should be easy to install and manage, reliable, and cost effective. The answer to this is a combination of webcams, PoE and high quality structured cabling.
This combination is naturally future proof because the open standards that underpin IP video ensure that any IP video surveillance solution will be interoperable and functional no matter what technology is developed in the future. And simply put, Power over Ethernet permits greater reliability of power supply than any other solution.
Justin Bewick is UK Sales Director of Reichle & De-Massari (R&M), and can be contacted via: justin.bewick@rdm.com
www.rdm.com
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