Where There’s a Wire (or Not), There’s a Way
What do fire alarms and barbed-wire fences have in common? Stay tuned …
Everyone knows one of the most expensive parts of a retrofit installation is labor. So it only stands to reason if a security dealer could find a simple and reliable alternate method to get alarm data through the system it would offer a competitive advantage.
This month we are going to take a look at various methods for transmitting security information over existing mediums. One of these techniques may offer a competitive alternative for the alarm installer or an added convenience to the alarm user.
Creative Early Signal Transporting
Now back to our barbed-wire story. Around the turn of the 19th century telephones were being installed everywhere. It was an exciting time because the technology enabled people, particularly in rural areas, to quickly communicate with each other. Not only were new phone connections popping up everywhere, but some also displayed examples of good old American technical ingenuity.
To many in those days, a wire was a wire. So if miles of new phone cable needed to be run to a ranch, why not try an existing wire that was already in place, such as the barbed wire on a fence?
Confirming what was believed to be an urban legend it was in fact used and did indeed work. However, it was very inefficient and went dead during rainstorms. The earth served as the phone circuit’s return. To improve signal transmission, farmers figured out ways to insulate the barbed wire using items such as glass beer bottles on the fence posts.
In the vast open plain regions of the United States, early phone systems including those transmitting over barbed wire, played an extra important role. Distinctive ringing patterns allowed farmers and their neighbors to receive warnings if there was an impending and quickly moving prairie grass fire. This was the common link between barbed-wire fences and fire alarm systems.
Now on to today’s alternative signaling methods.
Versatile UTP Offers PoE Capability
Probably the most versatile type of cabling in use today is unshielded twisted pair (UTP). Often referred to as category (Cat) cabling, this evenly twisted and electrically balanced cable carries digital data traffic as well as analog video and power over Ethernet (PoE).
The PoE standard (IEEE 802.2af) allows for devices such as CCTV cameras to require less than 13 watts of power, with the source device providing 15 watts. The 2-watt (20-percent) difference is for the power loss over the cabling itself. Coming soon is a PoE+ standard (IEEE 802.3at) that will allow for 25 watts of power at the device and 30 watts at the source. Power demands like this will require the use of multiple wires within the Cat cabling.
Devices such as PoE splitters can be used to provide power to noncompliant PoE devices requiring less than 13 watts (see photo at right). Multifunctional devices such as the new Netway HubWayEX active UTP transceiver hubs from Altronix can also transmit quality video signals up to a mile. Remember to use quality baluns on the camera end when converting video signal to UTP. More valuable information on some of these new PoE applications can be found in the Altronix product guide.
PLC CARVING OUT ITS PLACE
Every residential or commercial building has a distributed power system. The challenge to a systems installer is how to reliably use this existing cabling infrastructure.
Power line carrier (PLC) technology has been around for years with the early emergence of power signaling systems such as the X-10 platform. In recent years, manufacturers looking to increase reliability and application of PLC technology have formed alliances in search of the PLC Holy Grail, such as the HomePlug Powerline Alliance.
You may not be aware of this technology since many of its supporters hail from the computer and home automation industries. They include well known organizations such as Cisco, GE Energy, Comcast, NEC Electronics and Motorola. However, as the alliance makes inroads through the building automation market its presence will become more noticeable.
Russound, for instance, recently provided a new intercom application showing how nicely such products can utilize existing power lines in a residence (see Tool Tip box).
Wireless World Abuzz With Zigbee
Wireless communication is the ultimate medium with many alternate transmission technologies. One of the hottest is an open, ultra low power, mesh-based technology called Zigbee. Its worldwide proponent organization, the 450-members-strong Zigbee Alliance, is presently going from a development and research stage to true applications.
Look for this technology in upcoming product lines. Major organizations such as Schneider Electric are joining forces with others like Philips in the areas of home and building automation.
HDcctv Transforms Existing Analog
Recently, I have become aware of an exciting technology that marries existing analog CCTV systems and newer digital high definition (HD) cameras. It is called HDcctv and allows the placement of high performance IP HD cameras onto existing CCTV systems with standard RG-59U coaxial cable. This approach is being spearheaded by another organization called — you guessed it — the HDcctv Alliance.
The group is presently wrapping up an HDcctv interoperability standard (version 1.0) that will be available to its member companies. Once vendors start placing a special chip in cameras and other devices such as DVRs, digital HD data will be able to be sent over existing analog CCTV coax.
Additionally, the digital signals will be able to travel further than the standard 100-meter limitation of IP digital networks. Since an existing transport technology is being used the training curve for applying this new technology to existing systems will be minimal. I see exciting times ahead for the application of this alternative CCTV technology.
Alternatives Vie for Mainstream
As we watch these emergent technologies evolve in the coming months and years, it will be interesting to see which ones gain wide acceptance in the security industry. As with the innovation and creativity of barbed-wire telephones so long ago, new and exciting applications will undoubtedly spring forth from these modern communication methods.
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