Cabling is like the nervous system of the human body. A well-designed structured cabling system transports a wide array of information traffic serving many different functions. The information may range from control signals for the heating or cooling systems to the structure’s lighting systems. Security and life safety systems also use the cabling pathways. However, the dominant and primary function of the cabling systems seems to be communications.
Once the exclusive market of the regulated telephone companies, communication cabling has seen many changes in the past four decades. Technology and regulations have opened the world of communications and cabling to many different types of installation contractors (such as data networks, telephones, security, fire alarms, energy control, mechanical control, etc.). Adding to the frustration of consumers, technological advancements have produced more than 25 levels of cable performance products for the market in less than 25 years. Many cable systems were deemed obsolete as quickly as they were installed.
What kind of cable should we specify? There is no universal cabling solution to act as a barrier to obsolescence. ”Universal” does not fit in the world of cabling systems. We are left with a myriad of critical questions in order to decide on the cable and the topology best suited to fill the requirements. The millions of dollars spent on inadequate information transport systems is shocking, particularly in consideration of the value of the information.
The ideal cabling system provides a large number of services over a wide range of capabilities over time. It becomes an exercise in balancing cost and performance. Interoperability is crucial. Ultimately we may see the transmission requirements exceed the performance of unshielded twisted pair (UTP) copper cable. In the debate of copper versus fiber optic cable, many experts say we have reached that point. Deferring the change to fiber optics is no longer cost driven. Fiber and copper designs are very close to equal in current costs.
Today’s network manager is challenged to maintain a relationship with a contractor that will be a ready resource to install and maintain the information technology transport systems. Over the past twenty years, that contractor has increasingly become the electrical contractor.
“Low voltage communications [copper and fiber] electrical contractors are required to be licensed in most states. This license requirement offers a level of professional regulation and assurance to the public in an industry that was once only self regulated.” said Steve Dale, president of the National Low Voltage Contractors Association (NLVCA).
Cable management systems that record the asset are mostly myth. The horrible truth is that most companies do not have accurate records of the cabling systems. They have spent millions and cannot tell you what they have or where it is. No other area of corporate accounting allows such a situation to exist. The excuse is “It changes so much and so often that we can’t keep track.” Cable records are usually filed under Fiction or SCI-FI. Cabling systems are seemingly made of irrecoverable labor and hard to reuse or recycle materials. Once installed, the cabling system becomes a part of the structure’s asset and should be considered for other applications, if the primary functionality must be replaced by another faster transport platform. Cabling systems should no longer be considered “a throw away” expense.
Many companies abandon cable because they tend to migrate from one technology to another. Users build in incompatibility by installing different systems in different departments. Hardware, software and cabling systems are the key components in a communications system; each interacts with the other to provide network performance. Lower performance cabling imposes limitations on the whole system and tradeoffs abound. Lower quality transmission performance on the cabling will increase costs for hardware, maintenance and control. Of the three areas, software is the easiest to modify or replace. Cabling may not be the largest expense of the whole system, but it is systemically the area that generates the most “down time” and overall reduction of network performance. UTP cable is most susceptible to signal distortion and cross talk at higher frequencies. Difference in cross talk between shielded and unshielded pairs may be as high as 35 decibels at 10 megabits per second, and it increases as the frequency gets faster. Defenses have to be included in the topology design by the installing contractor. Emissions can come from a host of sources. This is another point in favor of the fiber optic cable, which is not influenced by EMP.
When integrating cable selection and network management to achieve tomorrow’s low voltage transmission requirements, select the contractor that will deliver well managed network infrastructure. Network managers should follow rigorous protocols when establishing material performance specifications. Testing shows us that the quality of UTP cable can vary greatly. Performance will change according to installation methods and environment. Cable performance will degrade over time. Additionally, temperature and humidity have negative effects on UTP cable performance. Always remember that standards are minimums when it comes to performance. Ask the manufacturer about typical headroom in their product designs.
Selecting the best choice for your contractor takes investigative skills, if you hope to realize the full value of your cabling infrastructure investment. Check out their credentials and visit their site whenever possible. Ask for their evaluation of your purchase specification and recommendations for ongoing moves, adds, and changes (MACs) activity. MACs are cabling systems’ weak point. To use an old adage “You can pay me now, or you can pay me later. But it’s always more expensive later.” Your contractor should be your partner on the journey to a new technology. Remember, planning is the most powerful tool in your network.
BISBEE is with Communication Planning Corp., a telecom and datacom design/build firm. He provides a free monthly summary of industry news on www.wireville.com.