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OBJECTIVES. 1. Explain the benefits of certifying cable installations. 2. Differentiate between a channel and a basic link. 3. Identify standard tests that should be performed on CAT5 cable runs to certify them. 4. Describe the functions typically associated with cable testing
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OBJECTIVES 1. Explain the benefits of certifying cable installations. 2. Differentiate between a channel and a basic link. 3. Identify standard tests that should be performed on CAT5 cable runs to certify them. 4. Describe the functions typically associated with cable testing instruments. 5. Describe the steps associated with testing and certifying basic links and channels.
TIA/EIA specifications, as outlined in TSB 67, require that four different tests be performed on CAT5 runs immediately after the cable is pulled, and terminated, in order to meet the certification guidelines and to avoid having to troubleshoot certain types of problems later. The four specified tests are: the Wire Map test the Length test the Attenuation test the NEXT test
Several additional tests that may be required under certain circumstances include: the Power Sum NEXT test the ELFEXT test the Power Sum ELFEXT test the Structural Return Loss (SRL) test the Attenuation-to-Crosstalk Ratio (ACR) test
Table 6-3: Industry Standards Performance Comparison (Worst-Case Channel Performance @ 100 MHz) * New requirements addressed in TSB95
Simple Rules for Testing: NEXT test must be performed at both ends of the run. Documentation of test results must be included. Cabling/components must not be moved during testing, or retesting will be required. End-user patch cords must be tested in place. It is suggested that patch cords be 3 meters, but this subject does not as yet fall into the scope of the TIA/EIA T568A standards. It is expected that future releases will deal with this issue.
The various features for this tester include: Before and after installation checkout Easy one-step operation 14 LEDs to confirm testing status Shuts off automatically to maximize power saving Tests for shorts, connections, non-parallel wiring, and 25/50-ohm BNC terminations Requires a 9-volt battery
LAB 16 OBJECTIVE Calibrating and Self-Testing Level II Testers To understand the procedure for properly calibrating the Level II testers, performing the self test, and documenting the test results
TIP Several warnings are listed in the manual that indicate the possibility of causing the meters to give erroneous test results. Become familiar with these error-causing situations.
TIP After a slight delay, during which time the control unit reports that the self-calibration procedure is in progress (and various clicks and beeps can be heard), the control unit will display the “SELF CALIBRATION COMPLETE” message.
TIP The screen menu returns to the SPECIAL FUNCTIONS display. Always remember to calibrate the Level II testers before using them.
TIP The Self Test function of the Level II testers is used to check the operation of both the control unit and the remote unit. It’s a good idea to run this test periodically, as well.
TIP After a slight delay, during which time the control unit reports that the self-test procedure is in progress (and various clicks and beeps can be heard), the control unit will display the “SELF TEST PASS” message.
TIP While the control unit is still displaying the SPECIAL FUNCTIONS screen, it would be a good idea to check the Battery Status function. Because the control unit was charged just prior to performing this procedure, it should indicate that fact during a check.
TIP If the status of the battery ever drops to a value such that the Level II testers would not operate properly, there will be a specific warning message displayed on the screen.
LAB 16 QUESTIONS When should the various cables be plugged into the Level II testers? 1
LAB 16 QUESTIONS How long should the Level II testers be charged, according to the users manual? 2
LAB 16 QUESTIONS What three measurements are taken during a self test between the control unit and the remote unit? 3
LAB 16 QUESTIONS When plugging a cable into the Level II testers, which unit (control or remote) should be connected first? 4
LAB 16 QUESTIONS How long is the cable that is used to calibrate the Level II testers? 5
LAB 16 QUESTIONS Under what circumstances should the Level II testers be calibrated? 6
LAB 16 QUESTIONS How long does the self-calibration test take to complete? 7
LAB 17 OBJECTIVE Setting Up Level II Testers To understand the procedure for properly setting up the Level II testers, and documenting the results
TIP Not all of the adjustable parameters displayed need to be tinkered with. Once some settings have been selected, they can normally be ignored from then on. Settings that may require periodic changes involve the particular test standard to be run and the type of cable to be tested.
TIP Notice that the very first parameter displayed is the TEST STANDARD, CABLE TYPE, because it is the parameter that most often needs to be adjusted.
TIP Notice that the bottom of the display indicates which of the four numbered buttons to press for the desired screen. You should now see the SELECT TEST STANDARD screen.
TIP You should now be looking at the SELECT CABLE TYPE screen.
TIP The control unit returns to the Page 1 display with the selections you just made highlighted. Any tests conducted at this point would expect to see CAT5 100-ohm UTP cable connected to the Level II testers.
TIP This parameter allows the user to edit the identification information that will appear in any reports that are generated by the Level II tester.