How low-voltage contractors can maximize labor hours and increase profits despite real-world installation obstacles.
For years now, low-voltage installers and integrators have heard the warnings that “digital IP integration” is coming, and they need to prepare for the changes that will ensue. Well the time has arrived when nearly every low-voltage system in the commercial space is either changing to IP or integrating IP into existing analog systems. There is a lot to absorb when it comes to IP integration. What types of systems are affected? What does IP actually mean, and what do installers need to know to be prepared for this paradigm shift to digital IP systems?
When you think of networks and data systems, places such as office buildings, hospitals, or educational facilities are what typically come to mind. Besides the typical computer network, there are other networked systems that are integrated into everyday life, hiding in plain sight. Systems like kiosks, electronic information signs, and transaction terminals at train stations, airports, parking garages, fuel stations, grocery stores, and convenience shops are just a few of the many examples of systems that are making the change to digital/IP communications. The common link between these systems is Ethernet and IP (Internet Protocol). Ethernet is flexible, inexpensive, and brings many benefits, but it also presents a variety of challenges to those who install the cabling infrastructure to support these systems.
As with many industries and technologies, cabling installation contractors are constantly trying to find the balance between winning bids and staying profitable. The two main costs of a job for an installer are the cost of materials and cost of labor.
Speaking specifically of the cabling materials, the costs for a job vary greatly based on the particular requirements of the contract, which may be as vague as “install network cabling for 500 workstations” to specifying the exact brand and model of the cable and connectors to be used on the project. When specific materials are called out, an installer finds himself on equal playing field with his competition. When a job is less specific, a contractor may be in the position of bidding against others who try to improve their odds of winning by using lesser quality materials.
On the labor side of the equation, contractors need to finish the job as quickly as possible to manage costs, but not at the expense of installation quality. Best practices for the installation of structured LAN cabling have been available for more than 20 years, but the fact remains that technicians may cut corners when trying to meet deadlines.
Differences in materials
Today, the most common variation of Ethernet deployed is Gigabit Ethernet (GbE), which has a transmission rate of 1,000 megabits per second (Mbps). Contrary to some misconceptions, GbE is specified to operate on Cat. 5e or better twisted-pair cabling. Some believe Cat. 6 is required, and this misconception stems from the early days of GbE. When first proposed, there were two sides debating how GbE should be deployed: There were 1,000Base-T and 1,000Base-TX technologies battling for market acceptance.
1,000Base-TX was specified to operate at a signal rate of 250 MHz and required Cat. 6 cabling. The advantage of this system was that lower cost network electronics (less sophisticated crosstalk cancellation) could be used with the higher performance Cat. 6 cabling, resulting in a lower total cost for new network installations.
The alternative 1,000Base-T system used more sophisticated and expensive network electronics but was able to operate at a signal rate of 100 MHz, meaning that existing 100 Mbps Fast Ethernet networks could be upgraded to GbE performance without re-cabling a facility. Even with the higher cost of network electronics, the draw of increasing network throughput by a factor of 10 by simply swapping out network equipment was enough to make 1,000Base-T the solution preferred by the market, resulting in the demise of 1,000Base-TX.
Installers who are aware of subtleties like this — and can explain the difference to their perspective customers — may have an advantage over their competition. By explaining why higher cost Cat. 6 is not necessary to achieve GbE performance, the installer can work with the client to reduce unnecessary costs. However, today’s installers must also be keenly aware that not all cable and connectors perform to the level marked on the product.
In a race to the bottom pricing for commodity materials like network cable and connectors, there are vendors in the market (e.g., Internet resellers) that prey on installers looking to tilt the profitability balance in their favor by saving money on materials. Two common methods of deceiving installers are rating materials as Cat. 5e or Cat. 6 that have not been independently verified or by outright counterfeiting of recognized name brands. In addition, UL and ETL performance markings are sometimes dishonestly used without the accompanying testing, leaving installers at risk of unknowingly using substandard materials.
Labor concerns and testing
Even with high-quality, name-brand materials, installers must also make the best use of labor time to keep a project profitable. Two of the quickest ways to turn a project from profitable to unprofitable are repeating work that should have been done properly the first time and dealing with disputes over the causes of network performance problems. Unfortunately, whenever questions about poor network performance arise, fingers are often pointed at the cable installer first. By this time, the cable installer is usually long gone, and it’s quite easy to blame the person who isn’t there to defend himself. What can the cabling installer do to protect profitability, reputation, and time? In many cases, proper testing of an installation can eliminate any question as to the cabling installation being the source of network performance issues.
Installation testing has traditionally come in two forms: verification and certification. Verification is also known as wiremap or “Modtap” testing. This form of testing is nothing more than a simple continuity test to ensure that the conductors of a twisted-pair cable are terminated to a connector in the correct order without any shorts, opens, crossed-pairs, or other physical faults. Unfortunately, wiremap testing does nothing to determine the performance of the cabling. Some installers mistakenly assume that if a cable link passes the wiremap test, it will pass data without any errors.
Certifiers were the first type of testers that measured the performance of a network cable. Certifiers measure a myriad of electrical characteristics of cables at frequencies as high as 1,000 MHz (not to be confused with 1,000 Mbps). Certifiers are governed by two international standards: TIA 568-C/1152-A and ISO 11801. These standards define the specific tests and pass/fail limits for various categories of twisted-pair cabling. For example, a Cat. 5e cabling link is certified by testing a number of parameters from 1 to 100 MHz, which examine the electrical properties of the cable. A passing test implies that the cable should support Gigabit Ethernet transmission even though contrary to popular belief the certification test does not transmit data across the cable.
Certifiers have been the accepted standard in data cable performance testing for 20 years and, until lately, they have been the only tool available that tested to a common standard, assuring users that regardless of brand, all testers met the same set of requirements. When
choosing a certifier, the differentiators are not the tests they perform or the accuracy of the tests. Instead, it’s the ancillary features that help a person decide which model to choose.
A different type of test called a transmission test offers installers another option to verify their work. Transmission testers have been used for years in the WAN/telecom industry but were not optimized for use in smaller Ethernet LANs. A transmission tester works by simulating a functional network and measuring the transfer of data rather than the electrical properties of a cable. In the case of GbE, the governing standard is the IEEE 802.3ab. The standard defines a number of data frames that must successfully transit over the cable compared to the number that are lost.
In the case of GbE, a total of 10 billion bits of data must be passed without losing a single bit to meet the requirement. LAN transmission testers can be used on live networks and are able to pass data through network switches to “stress test” an operational network for a fraction of the cost of a certifier. With speed and efficiency being so critical to profitability, transmission testers can be deployed on more service vehicles and used to test every job, regardless of the customer’s requirements. By performing a transmission test of installed cabling, the installer can rest assured that the combination of materials and workmanship come together to provide performance the client expects of the system.
Barrera is the global product manager of network cable testing for IDEAL Networks in Sycamore, Ill. He can be reached at firstname.lastname@example.org.