15 June 2011 Comments Off

DVR Input Connectors – The Good, the Bad and the Observation System

by Jennifer Spears

Here are the 3 most common analog style video input connectors you will find on cameras and DVRs. BNC, RCA and RJ11. I’ll discuss each briefly and tell you what to watch out for. (RJ45 connectors are used for Network and IP camera connections, and we will cover this style of connector in another article).

BNC is the best grade of connector and thankfully the most common these days. It is considered a more commercial grade connector and will last the longest with the best and clearest signal. Plus there is a “locking” feature machined into every connector. There are two little posts located on the sides of the female ends, and the male connector slides on and then locks into place with a quarter clockwise twist around these posts. This can really come in handy when you are running cable and trying to make solid connections.

RCA connectors are still out and about but they are a more residential grade connector. You will see this type of connector on the front or back of most TVs where you have video and audio inputs. There is nothing that locks this connector in place on the camera end or the DVR end so the probability of you having spontaneous disconnects goes way up. As long as you use some kind of electrical tape and wrap the ends of the cable attached to the camera pigtail, the likelihood of problems goes down to nil on that end.

Now for the Ugly – the RJ11 connector that comes on all observation systems. These systems and connectors are very outdated and cheap. Cheap in price, cheap in features, and completely lacking in tech support more often than not. This connector looks like a very small phone style plug. The wiring is very thin so interference is a big problem, it can’t travel over much distance at all – 40’ max, and it can become very brittle over a relatively short amount of time. There’s nothing like figuring out 3 months after you’ve spent your hard earned money, not to mention how many hours, pulling wires through your attic to figure out what you thought was a good deal just morphed into an albatross hanging around your neck. So take a deep breath and get prepared to pull all that junk cable back out and rerun the good stuff.

Now for a loaded topic – adapters. Can you adapt these video signals so they are compatible with a different DVR type, is a question I am asked a lot. BNC and RCA adapters are widely available and not very expensive. But you have to weigh the merits of can you against should you. One adapter normally doesn’t affect your video quality that negatively. But, you normally have a 3db loss in signal for every adapter you place between your camera and the DVR. That is compounded by all the other potential interference you have in the area from lighting, transient voltage, power outlets etc. RJ11 connectors cannot and should not be adapted. They transmit video, audio and power over a very small cable, and trying to break all of that out correctly is just asking for trouble.

A good rule of thumb is your video signal is only as good as your worst component. A great camera can look horrible if the cabling is sub par. Quality begets satisfaction. You really do get what you pay for when it comes to surveillance equipment for your home or business.

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