If the worst case margin falls within the field testers accuracy, it is marked with an asterisk (*). This is a requirement of ANSI/TIA-1152 and IEC 61935-1.
Let's find out which pair had a NEXT margin of 1.9 dB:
To better undestand this, let's draw a graph and put the limit line in as red. Then add the region representing the marginal band, shown in yellow. If the worst case margin should fall into this band, it is marked with an asterisk (*). It is important to understand that the width of the band changes with frequency.
Let's put our result above for Pair 3,6-4,5 on this graph:
It just falls within the accuracy band, hence the * on our test result.
Since accuracy is dependent upon frequency, it is possible to have two results with the same margin, but only one of them reported as marginal.
If you are looking for the specific frequency points of the marginal band, please click on the appropriate link below:
|Category 5e Permanent Link|
|Category 5e Channel|
|Category 6 Permanent Link|
|Category 6 Channel|
|Category 6A Permanent Link|
|Category 6A Channel|
|Class F Permanent Link|
|Class F Channel|
The accuracy bands programmed into the DTX CableAnalyzer are taken from the Independent Verification Testing with Underwriters Laboratories (UL).
Category 5e Permanent Link
You can also download these as a look up table.