Most installers adhere to cabling standards when they seem like the cheapest way to go; in reality, cutting corners, and taking short cuts cost you more in the long run. Picking and choosing parts of standards that make sense in the short term is a recipe for disaster.
I think we can all agree that home-run cabling is the best choice for wiring a residence. There’s little dispute that Cat 5 or Cat 5e cable is the choice for twisted pair cabling and that Series 6 Coax should be used for video. But what of the talk about EIA/TIA 570A standards, and what about levels one and two. What do these do for the builder, and what do they do for the installer?
These standards have their roots in commercial cabling, which have been a boon to the cabling industry. They were the catalyst for industry growth and brought cable installers into an entirely new market. Adherence to standards enabled installers to expand their businesses like never before.
Standards were good for manufacturers and good for consumers. Manufacturers grew their product line and expanded their offerings, while consumers benefited from new products and competition. More importantly, today consumers can count on a known level of performance and an accepted level of flexibility.
Once standards are adopted in the home building industry, all builders will be on an equal playing field. Understandably, standards-based cabling may be more expensive, adding a little to the cost of the house, but it will be the same for all builders. Builders that try to save a few dollars and skirt the standards will actually be put in a disadvantage. Knowledgeable competitors and homeowners will gladly point out builders that scrimp on the cabling standard, inferring that they probably also scrimp on the entire house.
The standard for a level one installation calls for a minimum of one Cat 5e or Cat 3 and one Series 6 coax to each outlet location. Level two installations call for two Cat 5 or Cat 5e cables and two Series 6 coax cables to each outlet. The common gripe lands in the bedroom. Homeowners want a phone at the head of the bed and a TV at the foot of the bed. So what’s the solution? To be standards-compliant, the outlet near the head of the bed should have a minimum of one four pair cable and a coax, and the outlet near the foot of the bed should have a minimum of one four pair and one coax cable.
So who needs a coax at the head of the bed and who needs a four pair cable at the foot of the bed? The answer is of course “Who knows?” Houses are built for forty years use or more; technology changes, users’ needs change. The idea is to do the best we can now within reasonable costs. Adding a second cable to a location where we are already pulling a cable adds little to the cost. If it were the difference between being standards-compliant and not standards-compliant, I’d go with the standard every time. This whole standards issue is advancing like an avalanche and builders nor installers should chance being known for not adhering to standards.
The second most common issue surrounds the RJ11 jack. Most phones come with a 6-position line cord with either 2 or four conductors. So why run four pair to a three pair jack? What do you do with the other pair? There are lots of opinions on this one.
The RJ11 line cord design fits the RJ45 jack. Some suggest that it’s a bad idea to plug an RJ11 plug into an RJ45 jack. However, the
Notice how pairs one and two align on both wiring schemes
There’s a new nomenclature evolving. Components will no longer be called RJ45 and RJ11. All installers know (or should know) that an RJ11 plug has six positions. Technically an RJ11 has six positions and only two conductors. Here’s where the confusion starts. Depending on whom you talk to, an RJ12 is six positions and four conductors and an RJ14 has six positions and six conductors. Other sources will tell you that an RJ14 has six positions and four conductors and an RJ25 has six positions and six conductors.
To confuse matters more, the USOC RJ45 has a wiring scheme that is different from both the 568A and 568B.
New definitions for the evolving nomenclature describe the number of positions and the number of conductors, and don’t reference wiring scheme at all. They refer only to positions and conductors. 8P8C is the new name for the old RJ45. It has eight pins and eight conductors. 6p6C is a six position, six-conductor plug. 6P4C is a plug with six positions and four conductors. No more RJ’s to confuse us.
So how did all of these standards evolve? In the early 80s, various computer networks had various proprietary wiring schemes; some used coax, some used shielded twisted pair, and some used unshielded twisted pair. Telephone systems had proprietary wiring, too. They all used unshielded twisted pair; some used one pair, some two pair, and some three pair.
Two things started happening. Computer network administrators didn’t like the expense and bulk of coax cabling, so they began using devices called baluns to eliminate coax cables. A balun would connect to a small section of coax near the terminal and a small section of coax near the main computer. Twisted pair ran between them. Ethernet devices were emerging that allowed the transmission of 10 Megabits on two twisted pair.
PBX’s started working on fewer pair when they became digital. Traditionally a PBX used an analog pair (pair 1) for actual voice transmission, a second pair, the data pair to transmit instructions to an electronic telephone and sometimes a third pair to power the telephone. In the emerging digital age, this quickly evolved into one or two pair for telephone.
Data rates were pretty slow by today’s standards; 10 Megabits for Ethernet and 16 Megabits for Token Ring.
In those days, AT&T made just about everything, including jacks and cable. But they weren’t big in coaxial cable. As baluns were eliminating the need for coax, AT&T figured out that you could mix voice and data on the same cable. They developed the AT&T PDS (Premise Distribution System) system to carry voice and data on the same four pair cable. Telecom managers and Information system managers didn’t jump in and embrace it, and there was reluctance from other manufacturers since this network plan claimed to be universal. A year or two later, the AT&T Systimax PDS was released. This system called for universal wiring, but it included two 4 pair cables per outlet location, one for voice and one for data.
As other manufacturers jumped on the bandwagon, as well as the EIA and the TIA, the standards system evolved into what we have today.
So Why 568A and 568B?
When it came to jacks, the standards defined two different wiring schemes, 568A and 568B. Standards were always influenced by the major manufacturers.
When the networking side of AT&T developed their ‘PDS’ system, they wanted to carry voice and PBX or key system data on two pair , and use the other two pair for computer data. At the same time, the electronics side developed their first electronic key telephone system, the Merlin. The developers wanted to keep the key system’s data pair far from the dirty analog signals on the voice pair, so they moved the data pair to the outer edges of the plug. Being a major driving force in the industry, AT&T was able to lobby this configuration into the standard.
But wait, AT&T wasn’t the only player on the block. Major PBX vendors like Northern Telecom (Nortel) liked the second pair right where it was, on both sides of the first pair. The second pair was always found on opposite sides of the first pair, this is how all two-line phones are wired. This became the 568A standard.
568A and 568B are both acceptable standards for commercial cabling. The EAI/TIA selected the 568A wiring scheme for the 570A residential standard because of the popularity of two line phones. You can plug a 6P4C (remember?) plug into an 8P8C jack and find pairs one and two in exactly the right position.
IT’S MORE THAN JUST WIRING
The standard defines more than just wiring. It gives safe parameters for minimum bend radius on the cables, and maximum pulling tension when installing the cables.
It also defines labeling. In commercial installations, labeling is one of the major ‘call back’ items on a completed job. Jacks have to be labeled, patch panels and termination panels have to be labeled and the cables themselves have to be labeled. I like using faceplates with built in label provisions to constantly remind installers that they have to be labeled. They don’t cost any more, and they sure help prevent those expensive callbacks
VERIFICATION OR CERTIFICATION
Testing is one of the toughest issues with residential installations. The EIA/TIA 570A standard requires certification. Most installers verify the installation but don’t certify.
Verification means that tests are made for continuity, and to make sure all of the wires are terminated in the right place. It may also include wire length measurements.
Certification does all of the above but also tests performance parameters like cross-talk, insertion loss, return loss, delay and a host of other parameters.
The difference in equipment amounts to about $5000. Certification meters aren’t cheap. It’s hard for an installation contractor to spend nearly $6000 for a device that may never pay for itself. When and if standards are universally accepted and enforced, all installations will require certification. All installation companies will be required to certify, so they’ll all need a meter – back to that level playing field again.
The ball is really in the builder’s court on the certification issue. If builders begin requiring certification, installers will begin certifying installations. The upside for builders is that it takes an established and well-funded installation firm to afford this type of equipment. Ideally this type of commitment will eliminate shoddy firms and raise the level for the entire industry.
So where do you find more about standards? Most major home networking equipment manufacturers have training programs in place. I’ve attended a number of these and never left impressed. Sure, a lot of time is spent on their specific products. Training is expensive and advertising is one way to help defray the costs. I’ve got no problem with that. Almost none talk about the details of the standards for the industry. They go little beyond “run two cables for this standard and four cables for the other”. They jump into 568A wiring with no explanation of why. Some include tips on how to circumvent the standards.
So where do you find more information? BICSI (Building Industry Consultant Service International) has residential cabling courses. CEDIA also offers training programs. Cisco Learning Institute has developed a Residential Networking course and a few community colleges, like Oakton Community College in Des Plaines Illinois, have developed their own courses. Private training organizations also offer seminars and video tape courses. Training is a required investment for an industry that is poised to grow and flourish.
Back to the Installer and the Builder
This whole home networking and standards based cabling initiative is being driven by affordable high speed Internet access to the home. Believe me, the Internet isn’t a passing fad; its not going away. Once people get comfortable with the Internet, home networking is just the next step. Beyond home networking is home automation and all of the other services in a home that can make out lives easier and more enjoyable.
The standards based cabling system is the foundation for these services. Commercial cabling would never have grown without standards. When builders and installers truly embrace the standards, the industry will grow exponentially. As long as we just run a few Cat 5e cables here and there, we’ll always be viewed as second rate.
Standards provide a level playing field for both the builder and the installer. They also provide a uniform and predictable infrastructure for the customer. The question is not whether standards will become universal, its when. Builders and installers that strictly implement standards now will develop their reputations early. Installers that skirt standards now will also be developing reputations.
About the Author
John Stagl has been in the cabling business for over 25 years. As a Member of BICSI and an RCDD (Registered Communications Distribution Designer) John was the subject matter expert for the Cisco Networking Academy Voice and Data Cabling course. John was instrumental in Cisco Learning Institute’s development of their Home Technology Integration course. He was also one of the subject matter experts for Comp/TIA’s HTI+ exam. Oakton Community College in Des Plaines Illinois contracted with Stagl’s firm, IDM Technologies to custom develop a residential technology course. Stagl’s firm also markets standards based wiring devices under their brand name IDM-Tech (www.idm-tech.com). For questions or additional information, contact firstname.lastname@example.org .