As in-home IP networking needs increase, installers and homeowners will benefit from using a home’s existing infrastructure

For High-Speed Home Retrofitting, Look to Coax

Ted Archer | Coaxsys, Inc.

For High-Speed Home Retrofitting,
Look to Coax

By Ted Archer Director of Marketing Coaxsys, Inc.

As in-home IP networking needs increase, installers and homeowners will benefit from using a home's existing infrastructure

Custom installations are conflicted creatures: On the one hand, they please customers with intricate and highly personalized home entertainment, security, and automation systems. On the other hand, the complexity of retrofitting a home places considerable labor demands on the installer and causes anxiety and hesitation for the homeowner.

What once was a simple TV rewiring installation has now become a network of media servers, security cameras, networked PVRs, Internet gaming consoles, and more. As customers' demands increase, it becomes more important for a home's network to be high-speed and reliable. As people increasingly distribute personalized content throughout their homes, a network's security becomes critical. And, with the number and complexity of connected devices increasing, installers and consumers are demanding robust networks that simplify installation and minimize damage to the home.

Today's "Typical" Installation

Most often, when people think of complex IP networks, they think to rewire homes with CAT-5 cable. The resulting network is high-speed, reliable, and secure; but, rewiring multiple rooms is a complicated, time consuming, and costly endeavor. Even if the home has no significant pain points (such as brick walls, delicate construction, long distances, or multiple stories), installers still spend valuable hours in constricted environments such as attics and crawl spaces. Furthermore, customers often cringe (and sometimes prevent installation) when they learn that a new set of holes will be punched in their walls.

Nevertheless, installers persist in installing CAT-5 networks because of their robust, high-speed, and reliable nature.

Recently, wireless technologies have expanded the home network by enabling data networking in places without a CAT-5 cable. And, there are some suggestions that wireless could be used as the home's IP backbone. However, there are three reasons that wireless will be relegated to IP network support roles for the indefinite future:

  1. Despite claims of high-speed 54Mbps data rates, 802.11 delivers only 10-15Mbps or less in practice,
  2. Wireless systems, while exceptional for short distances, deteriorate rapidly as distances increase and depending on a home's topology, and
  3. Wireless networks are inherently susceptible to security threats and interference from other devices.

Wireless network limitations aside, they will continue to play a valuable role in a home's IP network. However, homes with high-bandwidth, security, and distance demands will require a wired infrastructure. This brings us back to CAT-5 rewiring: Why would installers rewire-and consumers allow it-if the capability existed to deliver high speed, reliable, and secure IP networks over wires that already exist inside consumers' homes?

These Three Wires: A Look at the Common Home

Once an installer acknowledges the need for an alternative to rewiring homes with CAT-5, three possible alternatives quickly surface: phone lines, power lines, and coaxial cable. These three wires share one common trait: They are nearly universally installed in every U.S. home. With such broad scale availability, we must turn our attention toward the practicability of using each type of wiring as the IP backbone of the home.

Phone lines have been used for years now for data distribution and work quite well for providing moderate-speed Internet access (DSL). The fact that phone jacks can typically be found in multiple rooms throughout the home suggests that phone lines could, in theory, be well positioned to serve as a home's IP backbone. However, phone lines have two critical downfalls.

First, people tend to plug in phones in very distinct places: next to counters, at bedside tables, and in kitchens. The placement of phone jacks, then, is at odds with the desired location of an entertainment network, security system, or simply a television set. Because phone jacks tend to be physically located away from the media centers in a home, new wires would almost universally need to be pulled.

Secondly-and even more critically-plain old telephone lines cannot deliver the bandwidth necessary for today's bandwidth-rich applications, such as video. Even as Mbps compression rates for HD video streams move from double to single digits, the phone company's wire cannot support a home with multiple televisions, networked PVRs, and other high bandwidth applications. Furthermore, while compressed video will help wireless networks distribute more services, compression costs money; therefore, the less robust the network, the more advanced and expensive the video encoders and decoders must be.

Power lines solve the first problem discussed above. Because media centers require power outlets, they are almost universally available where the homeowner wishes to install a media center. Bandwidth, however, still poses a considerable problem: Fledgling technologies claim peak data rates of 14Mbps, which fails to even come close to the requirements of a media-rich home.

Additionally, the desire to transmit Ethernet over power lines faces another problem: interference. The surges and spikes inherent to power lines make data transfer a tricky proposition. In addition to being susceptible to reflections, crosstalk and degradation due to corrosion and age, power line technology is problematic from an FCC perspective: Any signal above 30MHz on power lines runs the risk of emitting noise into the air and upsetting the FCC.

Coaxial cable: An Unsuspecting IP Network Hero

Coaxial cable (coax), the sole remaining existing-wires solution within the home, is not only capable of delivering high bandwidth (100Mbps) without interference, but is also conveniently located near a home's media centers. Since coax was installed as the cable company's method of TV delivery, coax jacks are located throughout homes near where the homeowner wishes to watch television. Other devices-media servers, video game consoles, security systems-reside near the television also, making coax a convenient preexisting network.

Coax is shielded. Therefore, it does not suffer from cross talk, which means that interference is not an issue. Further, coax was intended to carry a wide spectrum of signals, from 0-2.4GHz. This broad spectrum enables multiple applications to travel on the same wire. Cable television typically operates in the 50MHz-860MHz frequency range, which leaves a significant frequency band available to transmit other data. Finally, compared to other wiring, coax wiring is relatively consistent from home to home. This means that installers and homeowners can depend on a coax network to perform and behave consistently.

Coax, then, already exists in homes and has large amounts of unused spectrum available to installers and homeowners. Instead of running new CAT-5 wiring, utilizing technologies that enable high-speed, reliable, and secure Ethernet-over-coax can save homeowners and installers' time and money without compromising network performance and security.

Our company, Coaxsys, has taken a simple approach to enabling Ethernet-over-coax-an approach embraced and deployed by dozens of service providers and custom installers around the country. The technology, TVnet, begins with basic Ethernet concepts such as packet framing, low bit error rate, and best effort protocols. It then expands on Ethernet by providing a Time Division Multiple Access (TDMA)-style Media Access Controller, which provides fair and equal access for all the devices that communicate over the network.

In simple terms, TVnet adapters receive an Ethernet signal, send Ethernet packets temporarily over coaxial cable, and then bring those packets back out through any coaxial jack in a home. TVnet connects media servers, video game consoles, security cameras, PCs, IPTV set-top-boxes-and any other Ethernet-ready device.

An IP network's most important characteristics are high speed, reliability, and security; any coaxial network must provide these elements in order to be Ethernet transparent, and thus a true substitute for CAT-5 rewiring. TVnet delivers a true and consistent 100Mbps (unlike the optimum operation rates posed by wireless and other technologies); is completely reliable; and cannot be snooped, hacked, or sniffed.

For more information about IP network installations over preexisting coax or to learn more about Coaxsys and TVnet, please visit

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