What’s Your Position on Transmission?

Five considerations when deploying or upgrading video signal transmission products


Encoding entails keeping the existing analog CCTV cameras and their corresponding media, be it coax, UTP or Fiber Optic and, using a video encoder/decoder, converting the video to Ethernet and inserting it onto the network through a network switch. The IP video is then directed to a network video recorder for monitoring and storage. Encoding is most likely the least expensive way to move to IP video. The encoding/decoding can be done at the remote location using video encoders or at the head-end, where the video can be transported over existing media and encoded before being inserted on to the network. Encoding at the remote location can be made with any of hundreds of video encoders available today. If the remote location is unconditioned, then a hardened encoder must be selected, and they are a little more difficult to find. The downside to encoding analog video is a limitation in video quality. As good as most analog cameras are, they are no match for today’s megapixel or high definition cameras.

Complete start over. A complete start over is likely the most costly, but is really the only way to truly future-proof your CCTV network. So, what do you need to be thinking about with respect to designing a network?

First, are you dropping cameras onto an existing network that you are using for normal company operations? That might not be the best planning, as IP video requires a lot of bandwidth. Disrupting or slowing down a company’s existing operational network might not be a prudent decision. Starting a new Ethernet network for security might be the safer bet in the long run.

When planning an IP Security network, for each location, you need to understand a current need for the number of devices, plus what you expect to need for expansion (vs. cost). You must also be able to determine and plan. Questions that will come up are:

• How much bandwidth will your devices need, across each segment and aggregated?

• What distances do you need to cover? The answer to this question determines what type of media you will need to select. For systems that use megapixel or HD IP cameras with distance considerations, single-mode fiber optic equipment is a safe choice.

• Are you using a Managed Ethernet Switch? A managed switch enables a user to control the IP address and features of the switch, giving the ability to precisely optimize and control traffic on the network; thus allowing the media to be used more efficiently. Using managed switches helps the chosen media — copper, fiber or wireless — to use the available bandwidth more efficiently.

Retrofit. Can I re-use existing cabling? If a fiber optic CCTV network is/was in place, chances are the fiber can be re-used with simple fiber optic media converters or switches with optical ports.

If the existing CCTV surveillance network is/was in place and the move to Ethernet is being made, IP video can be transported over the existing coax or UTP. Manufacturers can offer products that can extend distances over existing coax or UTP and support PoE, enabling the transmission of 100Mbps of Ethernet data to distances of approximately 600 meters without PoE or approximately 200-300 meters depending on IP camera power consumption with Class 3 13 watt PoE. There are variations to account for when using higher power, but these distances are good general recommendations. All are greater than the 100-meter generally accepted maximum distance for fast Ethernet.

 

4. Is wireless the right choice?

Wireless Ethernet transmission holds great potential, as it does not bind you to the logistics of running copper or fiber optic cables. It sounds simple, but there are many parameters that must be factored in to get a favorable installation. Network topology, obstacles, weather and time of year all have to be considered. But many wireless Ethernet product lines promise installation that is basically power, point and play — meaning you power up the access point and the field deployed client, point/aim the units using the antenna alignment tool and start transmitting Ethernet. Taking the complexity out of using wireless is a major advantage to acceptance and use. It is still not for every application, but it has its place.

 

5. Will the system operate seamlessly?

The promise of Ethernet and the entire IEE802.3 set of standards is to ensure that all IP devices that meet that standard theoretically operate seamlessly over the network. The reality of that promise is that many times, IP devices from different manufacturers do not seamlessly operate.

The safe bet for IP video transmission is to choose the transmission products from one manufacturer. If you can find a single source for your Ethernet transmission equipment, be it wireless Ethernet, Fiber Optic Ethernet, Ethernet over copper, Ethernet switches, media converters, having it all operate seamlessly is more likely to occur.