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Cool Tools: Qualification Testers

By Jeff Griffin | Oct 15, 2014
Ideal Networks SignalTEK® CT Gigabit cable performance tester..jpg

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For commercial structures, certification tests document that a building’s voice/data/video network complies with industry standards.


Qualification or performance testing can also confirm that local area network (LAN) installations meet component manufacturers’ install standards and should perform as specified. This testing had been considered optional for LANs in homes and apartments. 


“Qualification” is a general term used to describe such testing, and it sometimes is used interchangeably with verification testing and, incorrectly, residential certification.


“Our company now is using the term ‘performance testing’ to more accurately describe this process,” said Dan Payerle, business unit manager for network test products at Ideal Networks, a division of Ideal Industries.


While qualification tests typically have been thought of in terms of a building’s datacom system, today’s integrated systems include fire and security alarms, video surveillance, and control components. Each piece of the system must communicate with its host. Payerle said performance testing of cabling in homes and multiunit residential dwellings should not be considered optional anymore.


IP integration is here


“That means that all systems, including security, access control, home automation and voice/­data, are Ethernet-based,” Payerle said. “Ethernet allows every device in the systems to operate effectively on the same network so that an event on one system can trigger a series of actions by other systems.”


A solid cabling infrastructure is crucial to system operation, and it makes troubleshooting much easier when proof of performance tests eliminate cabling as a potential problem, according to Payerle. Because the systems are becoming more complicated and interconnected, ruling out communication errors from cabling should be the first step during installation.


When testing cabling, two types of standards can be used: one to determine pass/fail performance of cable, the other to meet signaling or transmission standards.


Payerle said cable testing standards, such as the ANSI/TIA-568 series, specify the electrical performance requirements of the cabling and do not necessarily consider the intended use or application.


“Today, other than analog voice, there is practically nothing other than Ethernet that is going to be sent over the cabling, including residential networks,” Payerle said. “Transmission requirements of Ethernet are defined by the IEEE 802.3 series of standards, the IEEE 802.3ab standard defining gigabit Ethernet. Most wired devices these days are equipped with gigabit Ethernet [GbE] ports versus 100 megabits-per-second [Mbps] fast Ethernet ports, and it is not uncommon to find gigabit Ethernet (1,000 Mbps) in residences.


“In residential buildings, whether single-­family or multidwelling, ‘prewiring’ was an upgrade option only a few years ago; now it’s standard practice. However, residential buildings are often wired on razor-thin margins, and the cabling systems that go into them may not support GbE, considered ‘minimum spec.’ Category 5e cabling is designed to support GbE transmission at up to 100 meters. Unfortunately, there are cable and connectors sold as Cat 5e-compliant, which are not. The result is that cable performance may not support error-free gigabit transmission, even when a link has been successfully tested with a wire map tester,” Payerle said.


Ultimately, data transmission matters most to customers.


“Network devices don’t care about the cabling,” Payerle said. “They will try to operate over whatever physical path is supplied. Therefore, testing the data as well as cabling makes the most sense in Ethernet networks.


“A data transmission tester behaves like a network device, except it reports errors and network limitations. Ethernet is designed to recover from errors without users knowing anything went wrong. A transmission tester provides a clear answer as to whether the network is capable of supplying the desired performance, regardless of cable category.”


Transmission testers are new to LAN installers. They have been in the WAN/telco environment for years as the standard way to test networks and can be complicated to configure and operate.


Ethernet transmission testers come in two categories: one category tests only passive cabling, and the other tests cabling sending data through switches.


“The ability to perform transmission testing through live Ethernet networks with easy-to-operate testers is new and gives integrators a tool to stress-test an existing network before upgrading or adding new IP [Internet protocol] systems,” Payerle said. “High-bandwidth systems—like IP CCTV—that are added to a network can negatively affect network performance. One IP camera isn’t going to generate enough data to cause problems, but a dozen high-resolution IP cameras can tax the switch that is handling the combined traffic of multiple cameras. The cameras will sense when the switch starts dropping frames and react by lowering their frame rate or increasing video compression, resulting in poor video quality.”


A transmission tester that features options to specify resolution, number of cameras and type of compression enables integrators to test the network before installation. The tester will be able to calculate a data rate based on the information entered and test the impact on the network before installers place a single camera. The results show whether the network infrastructure needs to be upgraded before adding a new IP CCTV system. The same applies for voice over IP and IP TV data.


Power over Ethernet (PoE) load testing is important because the voltage available at the end of a network drop depends on the gauge of the wire and the length of the run, Payerle said. A PoE load tester will apply a load to the PoE supply and tell the operator how much voltage, current and wattage is available at the outlet.


“PoE vastly simplifies the installation of Ethernet devices, eliminating the need to install separate electrical circuits for low power devices,” he said. “PoE supplies [direct current], making it susceptible to excess voltage drop from long drops or copper-clad aluminum twisted-pair cable that is sometimes unknowingly installed. Integrators who are installing and supporting the Ethernet devices attached to a network need to be able to test PoE.”


There are two types of PoE testing: one type checks for PoE availability, and the other type puts a load on the line, measuring true power available to the attached PoE device.


“Load tests eliminate a lot of troubleshooting time,” Payerle said. “If the specifications of a powered device require 12 watts of power and the circuit is capable of supplying just 10 watts, malfunction of the [powered device] is ruled out, and attention can be focused on the cabling or PoE supply devices.”


Ultimately, installers need to decide if they need a cable-only or cable and network tester.


“There are times when they may need both: equipping cable installation crews with a simple-to-use, cable-only transmission tester and equipping network setup and troubleshooting technicians with one that tests both cable and live networks,” Payerle said. “Network transmission testers usually have additional features like PoE load testing and Ethernet diagnostic tests.”


Ideal Networks has long produced wireless area network transmission testers and now has several options for LAN installers. The Ideal SignalTEK CT provides IEEE 802.3ab-compliant gigabit transmission testing over twisted-pair cable, and its SignalTEK II FO tests both cabling and live networks over copper or fiber.

About The Author

GRIFFIN, a construction journalist from Oklahoma City, can be reached at [email protected].

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