WireXpert NEXT Locator Function
This bulletin is for current and potential users of the WireXpert 4500.
The features and scenarios are relevant to WireXpert software version 7.4 and newer. All illustrations are taken from the WireXpert 4500 user interface screen.
What is NEXT Locator?
NEXT Locator is a diagnostic and troubleshooting tool that shows exactly where and what parts of a cable have unacceptable near-end crosstalk values. Near-End Crosstalk (NEXT) is an error condition that describes the occurrence of a signal from one wire pair radiating to and interfering with the signal of another wire pair. The reading below illustrates a typical NEXT locator view on a passing cable. Note that the NEXT values are highest at the near end and far end jack of this 17-foot-long permanent link cable, this is the most common scenario. Each of these pairs has NEXT values that pass the specific standard. If any of these pairs failed the standard, they would be shown with a red X respective to that pair.
Who should use NEXT Locator?
Anyone who would like the ability to troubleshoot near-end cross-talk issues within a cable. NEXT is a very commonly failed test criteria that is tested on tier 1 cable certifiers. Anytime a cable test fails due to the NEXT criteria the NEXT Locator allows you to troubleshoot this aspect of the cable performance. This function provides a clear graphical view of NEXT values over the length of the cable as well as the NEXT values of the specific pairs. This feedback is specific enough to aid the user with NEXT fails to decide if they need to punch down a specific jack pair, re-terminate entirely, or replace the entire cable.
Where is the Locator setting in the WireXpert?
Click on SETUP shortcut key
>TEST SETTINGS
>ADVANCED TEST OPTIONS
This photo above shows the Locator setting in the ON position.
Where is the Locator view in WireXpert?
The Locator view can be found on any pass or failed result when the Locator setting has been enabled.
When should NEXT Locator be used?
If you have a NEXT failure of your cable test, you will want to know where the NEXT failure is occurring. To find the location of the failure, use the NEXT Locator function.
Recall the below illustration of NEXT locator with all passing values. Note that NEXT values peak at the near and far jacks. Also the pairs in the near side jack termination in this test are the weaker of the 2 jacks (connections) in this cable. You can turn off the values specific to the various pairs by checking the boxes below in the screen.
Another scenario, shown below, we have a cable that has failed NEXT. After selecting the locator function, we can see the details of the particular NEXT failure. In this instance, the NEXT is significantly higher on pairs (1,2 )(7,8) and specifically at around 6.5 feet from the near side jack termination. This means that signals from pair 1,2 are interfering with pair 7,8. Note that this cable has a total length of around 13.7 feet. This type of NEXT issue is likely caused by a kinked cable at the noted distance of 6.5 feet. This scenario is helpful to demonstrate the ability of the NEXT locator to show the location of particular faults. Depending upon the technician’s preferences and the nature of the NEXT issue they may be able to re-terminate a particular jack or punch down a particular pair and avoid replacing the installed cable.
When should NEXT Locator not be used?
NEXT locator adds a second or so to the WireXpert 4500 Autotest time of each test when this feature is enabled. If a user is not interested in this information because NEXT is not a concern or the technician is looking for the fastest possible test time then they should disable this feature.
Tom Jallo
Softing Support