One would think designing large commerical cabling systems would be more difficult than residential, but that does not seem to be the case. Commercial systems today have a big advantage over residential, as a limited number of standards cover almost every application. In any given office, one needs to worry only about installing telephones, computers and perhaps a few security devices. Traditional telephones use twisted-pair wire with analog plain old telephone service (POTS) or proprietary digital systems at relatively low speeds. Voice over Internet protocol (VoIP) phones share the computer network cabling. Computers use Ethernet for cabled connections over copper to the desktop and fiber backbones or wireless connections. Commercial security and building management systems are migrating to using the same structured cabling as computers and phones. Thus, the choices are relatively easy to make.
Residences, however, have many more options. Phones, computers and some security systems can be connected just like a small office, but home automation and entertainment options are many and varied. Most have their own standards you must track down and try to understand. At a recent trade show, I counted seven different cabling types touted as “standards” in one vendor’s booth. Granted, many entertainment standards are designed around simply connecting clusters of devices, such as stereo systems, TVs with cable or satellite boxes, or home theater, not building permanent in-wall cabling connections. But standards that aim at permanent applications need to be understood in order to properly design home cabling.
Another, and perhaps the most important, difference between residential and commercial installations is the cabling’s physical location. Offices are designed for easy cabling installation and moves, adds and changes (MACs). From initial design, commercial buildings include areas set aside for equipment (telecom rooms) and cabling (pathways and spaces), generally designed around hardware meeting industry standards such as TIA 569. Cables run through open spaces, usually terminating at drops to modular furniture, making MACs and upgrades reasonably easy. Homes, however, usually put cables inside permanent walls and generally do not have areas set aside for placing and powering equipment.
This is a very important issue in residential cabling, both for single-family residences and multidwelling units (MDUs), which include apartments or condominiums. With so many different interconnection standards among entertainment devices and the rapid development of new technologies, such as TV over the Internet (IPTV), along with the obvious fact that people occupying the residence grow up and/or change often, this becomes a major challenge for the cabling contractor.
Finally, in commercial installations, the contractor, end-user and, perhaps, the architects or communications systems providers generally have the opportunity to discuss the cabling system before it is installed. Discussions include the overall goals of the design; types of communications systems to be accommodated; provisions for power, grounds and AC; documentation requirements; and even the provisions for MACs.
Unless you are dealing with a large developer, MDU or custom-designed home, this is less likely in residential work. While cabling contractors can bring lots of knowledge and experience to the project, they generally are not involved until it is too late to affect the design. Since the quality of the installation and the likelihood of providing better satisfaction to the residents depend heavily on the design, convincing developers or builders to have you involved as early in the process as possible is highly advisable.
The first consideration involves determining how to connect the residence to the incoming services or, more generally, any services that may be available to the residence. For single-family homes, that means providing conduits to the street for services, including electrical, telecom, CATV and an option for other communications services provided by the city or independents.
The conduits need to terminate at a convenient place at the residence, called a “distribution center” in TIA-570. Some building codes now are specifying an internal area for the communications connections, because many, such as fiber to the home (FTTH), have electronics that prefer more temperate indoor conditions rather than exposure to the elements. Wherever the termination occurs, provisions for installing equipment must be made, as many connections require more than passive cable connections today. FTTH requires an optical network interface (ONI). CATV will require a cable modem for the Internet connection and perhaps an amplifier if the home has many TV outlets. Municipal or independent networks also will require their interface boxes. Satellite TV, if used, also will connect to this location, usually through the attic from a roof-mounted antenna.
At this location, modular connections must be provided for all services to allow changes and troubleshooting. You also need to provide space for support equipment, such as routers and hubs to allow connecting multiple computers to the Internet or media center equipment that controls entertainment storage, selection and play. With more electronics involved, power becomes important, and astute users include uninterruptible power supplies (UPS) to ensure availability of services or at least controlled power shut-off in case of power failure or brownouts.
Having remodeled several houses of my own, I don’t believe that an in-wall box can possible provide adequate space. My current residence has two large ones; however, most of the equipment sits on a wire-rack shelf in a small closet we built just for the equipment we needed to support our home office and multiple room connections. A better solution would be in-wall termination boxes for all the cabling with outlets that stick through the covers for connection to electronic hardware on a shelf or rack.
What do you do in an MDU? There are two approaches. The traditional approach has one entry facility for all units with telephone and video cables to each unit. That’s OK for cable modems or DSL, but what about FTTH? One can locate the ONI in the entry facility and use video or data cables (Category 5e/6) to the unit, or one can provide space to bring fiber directly to the unit, the preferred method in the Far East where FTTH is much more widely used than in the United States.
Distributing through the home
From the distribution center, cables are connected to outlets in a star wiring architecture just like commercial cabling. TIA 570 offers two options for voice, data and video cabling inside the home. Grade 1 includes one Cat 5e cable for voice and/or data and one 75-ohm coax cable (RG-6) for video to each outlet. I highly advise against this option, as the new resident will be calling someone to angrily demand to know how they connect both a computer and phone at this location with only one cable. You can use a splitter, but finding one is not easy. You cannot get them at Radio Shack.
Grade 2 is the better way, with two Cat 5e (or, even better, Cat 6) and two coax cables per outlet. That means each outlet supports a computer, a phone and TV from CATV or satellite without modification. Grade 2 also allows for two optical fibers, but although I highly promote fiber, I cannot tell you today whether the fiber should be multimode, single-mode or plastic. Installing one is an iffy proposition.
One could use telephone wire and coax, I suppose. The FCC requires telephones use at least a Cat 3 four-pair cable, which is inadequate for computer use, but Cat 5e is about the same cost. One could use coax for networking, using the Multimedia Over Coax Alliance (MOCA) standard, which is being used in older residences by Verizon for its FTTH connections, but it is not widely available to the average consumer.
Stick to Grade 2 cabling, and use a bundled cable. Bundled cables have two Cat 5e/6 cables and two coax cables and install like one cable, reducing labor costs for pulling cable.
TIA 570’s outlet recommendations include one in the kitchen, one in a family room, one in a den or study and one per bedroom. Everyone who has children knows that one outlet in each bedroom is mandatory to maintain peace. But one needs to be in every room, and two are preferred for family rooms or dens, especially when considering the number of people working from home these days. At least one outlet should be placed outdoors, and one also should appear in the garage, especially if it also is a workshop.
Realize that you don’t necessarily have to use these just for computer hookups or TV. Having that outlet allows placing security cameras around the house, too. In fact, one can use power over Ethernet (PoE) from the distribution center to power surveillance cameras at any Cat 5e/6 outlet.
I have not mentioned wireless yet, but it’s part of the plan, just not as the primary connection. Laptops now are more popular than desktops, and mobility is a big selling point. Having a residential cabling system as described allows adding access points (wireless routers) anywhere in the house, providing the desired mobility, especially outdoors for those who like to work on the patio. Just don’t plan on using them as primary connections, especially when Internet protocol TV becomes more widely used, as the bandwidth requirements of streaming IPTV will overwhelm wireless networks, especially in a home where two, three or more viewers may be watching different programming at any one time.
Some residential systems are strictly custom and must be considered individually with the owner. Home entertainment, home theater and audio throughout the house usually requires custom design and some specialized cabling, such as speaker wires. Home automation is likewise custom, depending on the systems in the house and the degree of automation. Security systems (surveillance, intrusion and fire alarm) also require their own cabling and probably will be covered under building codes. Having a distribution center in the home where these systems may be sited adds convenience, especially since most security systems require a phone or Internet connection.
Pathways for residential cabling are the biggest problem. Sure, you can install the communications cabling just like electrical cable, sealed in the walls, as has been done with telephone cables for the last century. But with residential electronics changing all the time, it is folly to assume the cabling you install today will support all future applications. Ideally, one would install conduit to each outlet or baseboard pathways, so the cabling could be updated easily. This certainly is worth discussing with the developer and architect, as savvy homebuyers will understand the importance of providing for updates and, at least according to some builders I have discussed this with, are willing to pay extra for it.
HAYES is a VDV writer and trainer and the president of The Fiber Optic Association. Find him at www.JimHayes.com.