User`s guide

9H423-26 Cabling Requirements
A-12
• Return Loss - Return Loss is the measure of the degree of impedance matching
between cable and connector. A balanced input signal is applied to a connector
pair and the reflected signal is measured. (Reflections occur with mismatched
impedances.)
Return Loss requirements are not specified for Category 3 connectors because
they are not considered to have a significant effect on the link. Refer to
Table A-9.
• DC Resistance - The DC resistance between the input and output connections
of the connecting hardware for 100Ω cabling shall not exceed 0.3Ω. The DC
resistance is measured to determine the connector’s ability to transmit direct
current and low frequency signals.
See TIA/EIA 568A normative Annex A and Annex B for the reliability and
transmission testing of Connecting Hardware for 100Ω UTP cabling.
Table A-8. NEXT Loss (Worst Pair Combination) for 100 m
Freq (MHz) CAT 3 (dB) CAT 4 (dB) CAT 5 (dB)
1 586565
4 465865
8 405262
10 38 50 60
16 34 46 56
20 - 44 54
25 - - 52
31.25 - - 50
62.5 - - 44
100.0 - - 40
Table A-9. Return Loss
1 to 20 MHz 20 to 100 MHz
CAT 4 > 23 dB N/A
CAT 5 > 23 dB > 14 dB