In the past all home wiring was "daisy chained." That means that the cable, which came into the house from the street for the telephone, as well as electrical, was terminated to a distribution box. From there cable was pulled to the closest phone outlet and then the same cable was pulled to the next and the next, until the last one furthest from the distribution box was terminated. They were all connected -- as if in a chain. There might have been four phones hooked up to one continuous cable line, and you can only imagine the reception on the furthest one away from the initial hook-up. Crosstalk and static was the norm. If one failed then all the others beyond that one failed -- like the weakest link in a chain.

Today it has become a necessity to have a sensible structured cabling schematic installed in homes due to the increasing use of the Internet and additional PC's as well as other home office "toys" such as modems, faxes and cable TV. Residential applications cover more than just phone and power, they encompass data, video and home automation controls. Today homeowners expect multiple pre-wired jacks for high-speed computer networks, telephone and cable TV outlets in every room.

Daisy chain wiring is as outdated as the electrical standards that went along with that practice. Whereas the electrician can still install the electrical power outlets, today's cabling now rests on certified data cable installers. The layout is appropriately called "home run." There is one main distribution point or "home base", usually located near the electrical control box, that houses patch panel terminations for coax cable for audio and video control and twisted pair cable for voice and data. From there a dedicated cable is then run to each wall outlet, or jack, and is not tied into the others. Therefore, if one fails, the rest of the cable and connections can continue to work.

Many leading manufacturers of cable and connectivity equipment for commercial installations have entered the residential cabling market with similar cabling products installed in large office complexes. The main difference between residential and commercial structured cabling system is that residential installations include shorter runs and do not demand the bandwidth intensive backbone and sophisticated horizontal cables used in commercial environments.

But how can today's homeowners assure that they are getting reliable cabling since residential standards have just started to evolve? Just like the manufacturers of commercial cabling products entering the residential realm, hence major test companies are offering their equipment for operational analysis. However, only one, Microtest, Inc. (Phoenix, AZ, www.microtest.com ) specifically addressees unique cabling in the residential market by producing a dedicated line of handheld testers to perform verification testing for both UTP and coax for data, voice and video.

A growing need for residential cabling regulations

Whether it is a home, office or apartment, the common denominator is the pre-wiring and efficient cabling infrastructure, which has been tested and verified. For any structured cabling system, large or small, the key is to consider all possibilities of applications, both now and in the future and make sure that there is enough future proofing in the prewiring stages.

Although the basics for residential cabling can be derived from standards and practices in commercial cabling networking systems, it is a whole new arena for industry standards. Differences of single home units versus large office complexes include the type of cables and applications. Whereas commercial is data and voice intensive, residential also encompasses audio and video applications, as well. The type of cable for commercial applications is bandwidth intensive and requires higher speeds of backbone cables and horizontal cables - such as fiber and Category 6 - with longer runs. Cable types for residential include Category 3 UTP for voice, Category 5/5e UTP for data and voice, and coax for audio and visual. Often these cables can be pre-bundled to be pulled in tandem.

In the early 90's the Internet jump-started the need for high-speed residential cabling to replace plain old telephone wiring. But the cabling standards committees, such as TIA/EIA (Telecommunications Industry Association / Electronic Industry Association) along with the government-supported FCC (Federal Communications Commission) have not jumped in to regulate any residential cabling products and installation practices until half a decade later.

The FCC's Telecommunications Act of 1996 was the first major overhaul of telecommunications law in almost 62 years. The goal was to let anyone enter the communications business and redistribute business from the "Bell" monopoly. Therefore, it didn't matter who brought the cable from the street and into your home, the consumer had a choice of carriers. The same exists for the interior wiring, as well. Today there are now guidelines and regulations being set for cable installed within the walls of the home to assure that it can carry data needed for such applications including high-speed Internet.

In late 1999 the TIA/EIA published the TIA/EIA-570-A standard for residential telecommunications cabling, which encompasses the products, installation practices and testing. It is patterned after the ANSI/TIA/EIA-568A commercial building cabling standards as well as the TIA/EIA-569-A for commercial building pathways and TIA/EIA-758 for customer-owned outside plant cabling standards. Basically this attempts to standardize the requirements for new construction, additions and remodeled single and multi-tenant residential buildings in the realm of telecommunication services. This includes [you use 'encompasses' a lot!] more applications that the TIA/EIA-568A for commercial buildings as the TIA/EIA-570-A includes guidelines for installation of voice, data, video, multimedia, home automation, security, alarms and home automation systems.

Evolving Residential Standards

Today residential cabling standards for voice and data are still not as sophisticated as that of the commercial world, but the TIA/EIA-570-A document is a step in the right direction. The standards for providing the residential networking system need to apply to installation practices and testing procedures to guarantee the reliability and longevity of the installed system.

The TIA/EIA-570-A is broken into two acceptable grades which include Category 3, 5, 5e, coax and fiber. The two grades for the residential standards support telephone, television, data and multimedia. Grade 1 provides a generic cabling system that meets the minimum requirements for telecommunication services which includes one 4-pair UTP cable and associated connectors to meet or equal Category 3 cabling requirements and one 75-ohm coaxial cable. Grade 2 provides for a cabling system that meets the requirements for basic, advanced and multimedia telecommunication services. Cables specified for Grade 2 includes a minimum of two 4-pair UTP cables and associated connectors that meet or exceed the requirements for Category 5, two 75-ohm coaxial cabling and an optional 2-fiber fiber optic cable. Also, Category 5e is recommended in residential, but not required as it is in commercial buildings, replacing Category 5.

The standards for residential cabling recommend location requirements for distribution equipment, wall space allocation, electrical power, cabling topology and pathways, outlets, and cable protection. However, certain standards for commercial buildings may apply to multi-dwelling housing, such as an apartment complex, but are overkill for single unit residential environments. With fewer cables, conduits are smaller and therefore cable protection is more lenient in single dwellings. Maximum span lengths for commercial buildings are 90 meters for a link and 100 meters for a channel, but an average house typically does not need that reach in a star configuration. A minimum of one outlet is recommended per room, but addition outlets are recommended for every 12 feet of wall space.

Putting the standards to the test

The last step in assuring maximum system reliability is the testing procedures, which are crucial to verify the cables' performance to meet evolving standards for this emerging market. The main difference between testing cable for commercial applications and those in the residential arena is certification vs. verification.

Verification includes following the basic cable procedures and installation practices, which include cable placement, cable stress, cable protection and proper connectors to ensure cable continuity. Certification is much more stringent as it refers to specified measurement that must be compared and meet pre-defined commercial standards. For example, in certifying a Category 5e cable thousands of measurements are taken and processed in complex formulas to derive a pass/fail result. Some of these measurements result in testing crosstalk, far end crosstalk, wiremapping, length, delay, skew, and return loss.

"Verification does not attempt to measure the information-carrying capacity of the link because links in home networking are considerably shorter than commercial cabling links and so they do not suffer nearly as much from attenuation losses," explains Mark Johnston, RCDD, senior director of technology development for Microtest, Inc. (Phoenix, AZ). "Business systems are expected to place high demands on installed cabling. Such networks are 'certified' to meet standards. While this is desirable in residential applications as well, many contractors are content to perform basic verification tests instead ," he adds.

The TIA/EIA-570-A Residential standards include normative field test requirements of the cable and connecting hardware. Backbone testing includes continuity, shorts, crossed pairs, reversed pairs, split pairs and any other miswiring. The specific tests for the UTP cable and outlets include wire mapping, length, attenuation, near-end crosstalk. Additional field tests where Category 5e is installed include power sum near-end crosstalk loss, power sum equal level far-end crosstalk and return loss.

Some commercial testers, which are designed to perform complex testing for certification of structured cabling, may be excessive for residential applications and can be a signficant investment. For installers of residential cabling, Microtest Inc. introduced a new testing tool specifically designed for verifying cable applications in the home. Microtest MICROSCANNER™ Pro, part of the MICROTOOLS™ line, is the first designated residential tester to perform only the tests needed without the complexity or cost incurred for certifying commercial environments.

The MICROSCANNER Pro measures length, wiremapping and tests both coaxial and UTP cabling without having to use external adapters. For troubleshooting, it can pinpoint opens, shorts and crossed split pairs. The MICROSCANNER Pro's active network identification can determine if a network tap is operating at 10 Mbps, 100 Mbps or 10/100 Ethernet. It can also identify each room drops and outlets. Verifying these tests to meet the industry standards will assure proper cabling installation and will aid in the warranty of the home and avoid any liability issues for the contractor and installer.

To support the technology toys for the home, the cabling infrastructure installed today will need to support applications of the future. As technology in the home explodes with increased applications, efficient cabling will be a key in this market. But, the cabling system is only as good as its test results. Smart homes will be governed by the evolving standards. And smart installers will make sure that all systems have been tested to meet the standards. Contractors who have tested their work have the confidence that they have delivered a quality product that will meet the requirements of the ultimate user.

Carol Everett Oliver, principal of Everett Communications (Ashland, MA) is a freelance technical writer for the telecommunications industry. She can be reached at prcarol@yahoo.com .