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Alan – thank you.
One has to be careful reading cabling specifications to make sure they are looking at the descriptions of the ‘channel’ or ‘permanent link’, or “CP link”, which includes the connectors, as the specs you have sent are. Sometimes its confusing and you get just the ‘cable’ portion. The specs you sent specifically point out that channel specs, including resistance and resistance unbalance are met over the ALL temperatures, therefore we can leave the temperature part out, at least for the cabling channel.
I hope we’re not confused though, what Yair calls, Channel Pair to Pair resistance unbalance is still an undefined parameter here, so it is not governed by the statement of compliance – but I would expect that physics will imply that if the insertion loss and within-pair resistance and resistance unbalance, which are specified here are met, then pair-to-pair resistance unbalance will also be met. (note the resistance unbalance in Section 6.4.8 in your attachment is the ‘within-pair’ resistance unbalance, currently specified for PoE and PoE+ in IEEE Std. 802.3-2012, clause 126.96.36.199.)
Principal, CME Consulting
Experts in Advanced PHYsical Communications Technology
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The ISO/IEC 11801 channel DC loop resistance requirements are for the temperature the cabling is designed to be used. ISO/IEC SC25 WG3 did worst case calculations some time ago to verify that this was practical.
I have copied the relevant DC loop resistance and DC resistance unbalance requirements from ISO/IEC 11801 for reference (these are attached).
Best regards, Alan