Play the ‘Match Game’ for Winning Installations
Whether you are selling or buying an integrated security system, one of the most important technical areas is understanding how to match different communication and transmission technologies. On any given day, the systems integrator is asking, “Let’s see, today will I be matching and converting USB, SCADA, NTSC, MPEG, RS-232, RS-485, RS-422, UTP, Cat 5, HDTV, Wiegand, F2F, bar code or different system databases?”
Events such as 9/11 have pushed the physical scope of today’s security technology integration. In the past, buildings that had only a few CCTV cameras now have hundreds — including in every hallway and extending to the far edges of the outer perimeter. When an access control manufacturer specifies that its equipment has an operating range of just a few hundred feet, should that place a limitation on the operating range of the equipment?
Heck no! Learning to use third-party equipment, such as those from Cypress Computer Systems, can add another dimension to security system design. These cost-effective modules will match and convert signals to allow access control readers to be more than 10,000 feet away, or well beyond the scope of the original manufacturer.
It’s all about learning how to play the “Match Game” — no Gene Rayburn or Charles Nelson Reilly required!
UTP Keeps Proper Balance
If we are going to send different types of signals long distances, we first need to have a signal path that can carry low-level signals without outside interference. While networks and digital technology are coming on strong, many experienced integrators will tell you that the analog world is still thriving.
Yes, I know the song: Analog signals are hard to transmit over cable, especially with all the electronic noise around us today. While this is true, it should not deter us from using analog signals with the proper noise-canceling technology.
Have you seen the new noise-canceling headphones now out on the market? No matter how much ambient noise is in the air, a person puts these headphones on and only hears the music, without any outside interference. For every bit of outside noise, the internal electronics of the headphones sample and cancel that noise from getting to the eardrums of the listener.
Unshielded Twisted Pair (UTP) technology works on a similar principle. As noise is induced on one wire, the opposite twisted cable in the electrically balanced wire pair cancels it. Using this concept, low-level signals can be sent down a pair of twisted wires over great distances and not be influenced by outside noise.
One of the extra advantages of using this technology is that twisted-pair (Category 2 or better) is everywhere. With UTP technology, signals such as CCTV signals can easily be sent. One of my favorite examples is when you have little or no conduit space to run camera video between buildings, but you do have an existing spare phone extension to send this video over.
Can You Pronounce ‘Balun’?
Now that we have learned the principles of UTP, we should be able to take a little 1V video signal and send it long distance through the UTP, right?
Nope. We have to first use a device called a balun, which actually stands for “balanced-unbalanced.” Remember our discussion on the previous page about a balanced cable? The balun allows us to take an unbalanced signal such as a video signal traveling in a coax to ground and convert it to a balanced signal for our UTP cable.
One recent impressive application of this technology is a new product released by MuxLab Inc. The company has a new device called the “quad video balun” (see photo on page 28 of August issue) that allows four composite video channels over a Cat 5 for a distance up to 2,200 feet. See how cool this conversion stuff can be?
Use Lowest Common Denominator
Remember back in grade school when you had to add fractions like and ? The teacher taught you to find the lowest common denominator (LCD). You probably said to yourself, “I will never see this in real life.” Well, while you may be right about those nasty numbers, you were wrong about the concept of a LCD. It is probably still the most practiced concept in integrating systems.
By matching different technologies to a lower common denominator, you can easily go from one system to another. Let’s take a look at a couple of technology LCD examples.
Recently, I observed an access system being installed for a company that had to interface with its existing Supervisory Control and Data Acquisition (SCADA) communication system. SCADA is a technology communications protocol that has been used for many years by various industries to remotely control everything from pumps to nuclear reactors.
Rather than trying to have one communication technology talk to another, an LCD was found that was a relay bank (see photo on page 30). Yes, the lonely relay, which is one of the security industry’s oldest devices and still one of the best for system isolation, control and interfacing.
Through the years, I have had to work with data from a variety of databases in different access control systems. In some instances, it was important for one system to be able to read and either import or export data such as names, ID numbers, etc. from one system to the other. Again, rather than have to worry about changing the programming so one proprietary language can talk to the other, how about finding a database LCD for the conversion?
I have found that almost any database system and language can export its data into what is called American Standard Code for Information Interchange (ASCII) delimited files, which is just plain text without any formatting. Delimiting the ASCII text in a file is done by having special characters, such as a comma or a tab, separate fields like first name, last name in the database. This type of data can be easily moved from one database to another, as both understand it. This is another example of matching data with a LCD tool. Open Systems/Standards Lie Ahead
Much of what I have talked about in this article deals with current technology, which I expect to still be around for some time. All that being said, having to match and convert various technologies will gradually become a thing of the past due to the move to open platforms in which many security systems will be able to more directly talk to each other.
Organizations such as the Security Industry Association (SIA) are working on standards like the Open Systems Integration and Performance Standards (OSIPS), which will help as more systems move to pure network communications.
Another open standard that you will start to see more and more in systems is extensible markup language (XML). This communication standard has evolved from the Internet and network-based HTML language. An example of the interchange- ability of XML is its current pop- ularity in Internet RSS news med- ia feeds.
In the past, security devices such as PIR motion sensors gave our basic, or LCD, output of a relay normally open and normally closed. I have heard rumors that a new generation of motion sensors is being worked on that will not just transmit alarms but also send sensing data using open communication standards such as XML.
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