Bernard, thanks for that update.
How well do you think that this multi-pair scheme will work? I have come across other four pair schemes that have not met with much success, including AT*T's 622 ATM in the past, and HP's category 3 100Mb/s scheme.
A funny thing happens when you go to inspect that "embedded" cabling. You find that in many instances the cable has been split from its original single 4-pair jack constitution, to two 2-pair jacks.
Another potential problem in using embedded cabling, although less likely than the former, is the group delays that exist on some of the older Cat 5. If you recall, there was an attempt to save on the resins that were used in the plenum grade cabling insulation, due to an alleged shortage of supply several years ago, and the fourth pair in the bundle was skimped on intentionally to conserve this material. This resulted in affecting its capacitive reactance, and causing its phase shift characteristic to change from the other three pairs, considerably. If this had an impact on 25 Mbps per pair, it should have an even greater effect on 250 Mbps per pair, wouldn't you think? Or, am I making too much out of this? I any event, I thought it was interesting enough to mention here. What the heck! <s>
These anomalies, despite all the best advice and warnings to the contrary by diligent consultants at the time of installation! <smiles>
Regards, Frank C. |
