Below is a complete method statement that can be followed for performing testing & commissioning of structured cabling system including voice, telephone and data systems.
Copper Cable Testing & Commissioning Method Statement
- Characterizing cabling provides useful data for the support of future equipment application. The verification of the transmission performance of cable plant through field measurements results in a more professional hand-off from the cabling installation contractor to the customer. This should improve the overall effectiveness of providing premises networking solutions, as well as a baseline for future troubleshooting, resulting in higher customer satisfaction.
- This chapter addresses the field testing of unshielded twisted-pair (UTP and optical Fiber cables). This media is defined in ANSI/TIA/EIA-568-A, Commercial Building Telecommunications Cabling Standard.
- Each field tester is designed to perform a specific function or a range of functions required for the testing and certification of a specific cable type. They vary greatly in capability and price. It is necessary to select the most cost effective unit available to perform the specific tests required.
Induction amplifier/tone generator
- Also known as a toner or cable tracer, this field test equipment provides the ability to identify a specific pair by generating a tone on one end of the pair, with an inductive amplifier identifying it at the opposite end. Some induction amplifiers also provide the ability to trace the pair throughout its entire length by this same method. This field test equipment is primarily used for cable identification and troubleshooting. Most units are now a combination of tone generator and continuity tester, commonly known as a wand and toner set.
Wire map testers
- Wire map testers, also known as pair scanners, are low-cost cable testers that usually test for opens, shorts, crossed pairs, and miss wires in either a 4-pair or 25-pair cable. Some testers in this category will also test for split pairs. These units are good for quick, basic tests, but lack the sophisticated diagnostic capabilities of more expensive testers. Most testers in this category are designed exclusively for UTP.
Cable-end locator kit
- Sometimes called an office locator kit, this is a set of numbered 8-pin modular plugs which can be identified by the cable test equipment. The standard practice is to insert the plugs into outlets in the work area, then search with the tester until it finds the plug at the opposite end of the cable.
Certification field testers
- Certification field testers are used to verify that a cabling system meets the transmission performance requirements as specified in TIA/EIA TSB-67. All of these units will test a cabling system up to at least 100 MHz, and in the auto test mode, include length, attenuation, wire map, and near-end crosstalk (NEXT) tests.
- When the field tester is operated in auto test mode, it compares the actual measured values with required values for Category 3, 4, or 5, and displays pass or fail for the entire battery of tests. The tester will also display pass or fail and the actual tested values for each parameter. These testers are capable of other measurements, including impedance, capacitance, resistance, delay, delay skew, equal level far-end crosstalk (ELFEXT ), and attenuation-to-crosstalk ratio (ACR) calculations. In addition to the TIA/EIA TSB-67 standard, they also include the classes of ISO/IEC and the pass/fail criteria in their database. Each certification field tester is configured to test continuity and length of coax. Several have the ability, with an add-on module, to perform the power meter test for attenuation of optical cable Fiber. Certification testers can store test data and export it to a database or output it to a printer.
- Most field testers also have the ability to be controlled by a PC and download and store directly to the PC hard drive or floppy disk.
Certification test sets
- Certification test units will test a UTP cabling system measure and record the following parameters:
- Wire map
- Additional parameters which may be measured or calculated and recorded include:
- Return loss
- Propagation delay
- Delay skew
- Power sum NEXT
- Power sum ACR
- Power sum ELFEXT
- The Auto test feature compares the actual measured values with required values for Category 3, 4, or 5 performance and displays pass or fail for the entire battery of tests. The certification test equipment will also display pass or fail and the actual measured values for each test, individually. These units are capable of other tests, including impedance, capacitance, and loop resistance. Certification testers can store data and export it to a database or output it to a printer.
- In the event that a link fails to meet specifications, it is time to stop and understand what may be the cause of the failure. Note that a failure is a measurement failure and could be caused by the cabling, components, test equipment, or poor installation practices.
- Follow the procedures below to investigate a failure:
- Ensure that the tester is working properly by checking it against the calibration link mentioned earlier. If this link measures within the accuracy limit of its original measurement (maximum 1.5 dB for NEXT and 1 dB for attenuation), the field tester appears to be functioning properly.
- Follow the troubleshooting guidelines in Table 8.1 for various problems.
- If the trouble has been identified, take corrective action to fix the cabling.
- Retest to ensure that the corrective action has worked effectively.
Fiber Optic Cable Testing & Commissioning Method Statement
- The testing of an optical Fiber link is conducted for the following reasons:
- Pre-installation testing
- Acceptance testing
- Preventive maintenance testing
- Pre-installation testing is performed on a reel of optical Fiber cable after it is received from the supplier and before it is installed on the job. The benefits of pre-installation testing are verification of the following:
- Cable has not been damaged during shipment.
- Cable contains no factory defects.
- Attenuation of the Fiber matches the factory test report which should be shipped with each reel of cable (if shipped by the manufacturer).
- If a defect is found during the pre-installation testing, the shipper, supplier, or manufacturer should be contacted for replacement. If the cabling installer does not carry out pre-installation testing and then finds a defect after installation, there is no way to prove that the installation crew did not cause the defect. A few hours spent on pre-installation testing may save thousands of dollars in replacing defective cable.
- Pre-installation testing can be per formed with an optical fiber flashlight, depending on the length of fiber, a light source and power meter. An optical fiber cable on a spool or reel should be ordered wound so that both ends of the cable are accessible for testing. To use a light source and power meter, connectors or reusable mechanical splices must be installed on each end of every fiber strand.
- A light source and power meter can only measure the attenuation (end to end signal loss) of the fiber. If a value is not within the expected range, the power meter cannot determine the nature or location of the defect.
- An Power Meter can measure the following:
- Distance to a point of high attenuation.
- Optical loss per unit of measure (dB).
- Continuity testing end to end of each fiber.
- The following standards are applicable to premises optical fiber cable testing:
- ANSI/TIA/EIA-455-171A Currently Standards Proposal No. 3017, Proposed Revision of EIA-455-171 FOTP-171 “Attenuation by Substitution Measurement for Short Length Multimode and Graded Index and Singlemode Optical Fiber Cable Assemblies.”
- ANSI/EIA/TIA-455-61 Currently Standard Proposal No. 2837-B, Proposed Revision of EIA/TIA-455-61, FOTP-61 “Measurement of Fiber or Cable Attenuation.”
- ANSI/TIA/EIA-526-7 Currently Standard Proposal No. 2974-B, Proposed New OFSTP-7 “Measurement of Optical Power Loss of Installed Singlemode Fiber Cable Plant.”
- EIA/TIA-526-14A Currently Standard Proposal No. 2981, Proposed Revision of EIA/TIA-526-14 OFSTP-14 “Optical Power Loss Measurements of Installed Multimode Fiber Cable Plant.”
- An optical Fiber link is a path consisting of one strand of Fiber which has a connector on both ends. Optical Fiber links normally begin and end in administration housings called Fiber distribution units. Links are connected to electronic devices such as hubs, multiplexers, and routers with jumpers. Multiple links can be connected in the Fiber distribution units using jumpers to create circuits.
- An optical Fiber link or circuit should be tested before it is put into service and at other times, such as during troubleshooting. A light source and power meter can be used to measure the attenuation of the optical Fiber link or circuit.
The following are the benefits of acceptance testing:
- Verifies that the total attenuation of all passive components in the link is within the design parameters (loss budget).
- Verifies that the passive components were installed properly.
- Minimizes downtime due to maintenance on improperly installed passive components.
- Establishes accountability when circuits are configured with multiple links connected together and installed by more than one vendor.
- Provides a benchmark for comparing future measurements.
- Acceptance testing of intra-building Fiber is most often performed with a light source and power meter. Two people may be required to perform this test. They may need some form of communications such as a Fiber talk set, portable two way radios, or telephones. The light source and power meter are capable of a more accurate insertion loss attenuation measurement than an OTDR.
- Acceptance testing of a new installation employing a light source and power meter should be performed on individual links and not on a circuit that has one or more jumpers. This is because the circuit may be reconfigured in the future and the attenuation value for each link will be needed by the customer or technician to properly design the new configuration. The results of each measurement should be recorded on the optical Fiber link attenuation record.
POWER Meter Configuration
- Choosing the configuration of a Power Meter depends on the Fiber to be tested. Power Meter can measure one Fiber type at a time single mode or multimode. Either a single or dual wavelength measuring capability for each type of Fiber can be selected. Thus, Power Meter are available to test 850 nm and/or 1300 nm multimode or 1300 nm and/or 1550 nm single mode.
Once a Power Meter has been properly configured for the Fiber system to be measured, the test can be made. There are few decisions which must be made in determining the instrument setup conditions to get the best results. Many of these measurement parameters only need to be set once and will remain in the instrument’s memory. If trace data can be stored in the Power Meter memory or on a memory card, the setup information is also normally recalled when the trace is recalled back to the screen.