Cat 5 Wire -- It's Not Just for Data Anymore!

Posted by Avi Rosenthal on Oct 20, 2005

We all know about Cat 5 wire, that ubiquitous conduit that delivers all of our data safe and sound. But did you know that there is much more you can deliver with that same piece of wire?

By design, Cat 5 is actually eight separate wires bundled together: they are separated into pairs and twisted together at different rates, and then the twisted pairs are twisted around each other. The rate of twist of each pair is different, creating an environment that is not easily effected by other radio frequency interference, which negates the need for any type of shielding. And contrary to popular belief, the rate is not five twists per inch: The name Cat 5 is derived from the fact that it was the 5th category of wire that was sanctioned by the EIA/TIA. There is now a Cat 6 and even a Cat 7 being developed with each step an improvement over the former.

The speed of the data transmission over Cat 5 has increased as new versions of Cat 5 have been released. Currently, the Cat 5e standard that has been adopted is capable of 400Mb/s, or 400,000,000 bits each second. This gives it the capability to move great big chunks of data very quickly. However, because it is still just eight pieces of cable bound together, it can do so much more. The physical connections can create the ability to send audio, voice, and even video, without the need to run additional cables.

In some cases the Cat 5 can be used for multiple purposes at once (i.e. voice and data). Most people don't know that the original intent of the four pairs was to carry voice on two and data on the other two. Still, most of the "exotic" uses for Cat 5 are single use.

For a long time, Cat 5 has been used for distributing audio around the home. Numerous companies have used this technology for a few years to send the audio, control the devices via infrared, raise and lower the volume in the room and even the rest of the house. Some use the A-Bus standard, others, like the On-Q lyriQ™, use their own system. Each consists of an amplified keypad and a central hub, located behind the entertainment center. A single Cat 5 wire will transmit not only the audio but also the control and commands for the whole system. Some, like the On-Q lyriQ™, come with a remote control that allows you to control the whole house from any location.

Another use for Cat is video. Although some video is sent via a computer, this is considered data and not true video because it is normally compressed, or converted to ones and zeros, so that it can be transmitted easily. A TIVO will do this to send a recording from one TIVO to another. It is possible to send true video over a Cat 5 wire; for example, some cameras are wired using a single Cat 5 to not only deliver the video signal, but to power the camera as well. This makes them very easy to install, even after the home is built, if it is prewired with ample amounts of Cat 5. In this case, a camera can be added to a room that has a spare Cat 5 wire wired to it.

The newest use for Cat 5 is for intercom systems. Last year, Greyfox developed a brand-new type of home intercom that used a single Cat 5 wire to connect the rooms of the house. Instead of a big bulky intercom box in the kitchen, the Greyfox box is now about the size of three light switches. And if there is ample Cat 5 in the home, it is simple to add.

Now that these different sub-systems are using Cat 5 as their method of communication and connection, it will be even easier to develop solutions that allow all of these devices to communicate and connect with each other in the future.