Can anyone tell me if the faceplace / RJ 45 socket units for Cat 3 cabling would be suitable for reuse in a Cat 5 installation? (I realise that the cable is different, but I am wondering if the wall sockets are).
Thanks in advance.
The only thing to watch, is that the sockets are CAT5 compliant, if you're planning on running faster than 10baseT.
Generally not. Very few people would install Cat5 jacks (sockets) on Cat3 cabling. They might not even have been available at the time. Cat5 jacks are different (usually have a small PC board) to reduce crosstalk.
The reverse is far more likely and sensible. Some people today are terminating Cat6 cable with Cat5e jacks, waiting to see if something new crops up to use the extra bandwidth of Cat6 cable while not paying the high price of Cat6 jacks.
-- Robert
That'd be a long wait! ;-) The worst part of it though: when the wait is over, they will realize that the old CAT6 cable does not cut it, too. All the new developments around the "augmented" CAT6 I know of (aimed at supporting 10G Ethernet for 100 meters) I know of revolve around improving on the cable, not so much on the jack. That would essentially render the idea of CAT5E jacks on CAT6 cable for future proofing useless.
What's more, having to transition the signal from CAT5E parts on CAT6 and back introduces extra return loss, which probably nullifies any advantage of using the CAT6 cable in the first place.
That'd be a long wait! ;-) The worst part of it though: when the wait is over, they will realize that the old CAT6 cable does not cut it, too. All the new developments around the "augmented" CAT6 I know of (aimed at supporting 10G Ethernet for 100 meters) I know of revolve around improving on the cable, not so much on the jack. That would essentially render the idea of CAT5E jacks on CAT6 cable for future proofing useless.
What's more, having to transition the signal from CAT5E parts on CAT6 and back introduces extra return loss, which probably nullifies any advantage of using the CAT6 cable in the first place.
That'd be a long wait! ;-) The worst part of it though: when the wait is over, they will realize that the old CAT6 cable does not cut it, too. All the new developments around the "augmented" CAT6 I know of (aimed at supporting 10G Ethernet for 100 meters) I know of revolve around improving on the cable, not so much on the jack. That would essentially render the idea of CAT5E jacks on CAT6 cable for future proofing useless.
What's more, having to transition the signal from CAT5E parts on CAT6 and back introduces extra return loss, which probably nullifies any advantage of using the CAT6 cable in the first place.
Why? The impedence of Cat5e & Cat6 is the same. There are no extra parts.
-- Robert
Well, there is always the DC resistance that's different for mostly 23AWG CAT6 and always 24AWG CAT5E. That should only matter for lower frequencies though.
With regards to the impedance that matter for high-frequency apps: only the STANDARD 100 Ohm impedance is the same for CAT6 and CAT5E. In reality though what happens is: CAT5E cables normally fluctuate within the entire allowed region between 85 and 115 Ohm. With a good manufacturer you'll find the impedance consistent within a series of boxes, but then slightly changing as you go to the next batch. With some manufacturers it even fluctuates between pulls from the same box!
CAT6 cables are usually made to stricter standards. Some time ago I have participated in series of tests (for reasons outside the scope of this message) of cables by a reputable manufacturer. What we have found is that impedance for the CAT6 cable tends to be within the higher portion of the allowable range. In our case it was between 106 and 115 Ohm. The manufacturer would not comment on that, but we concluded that is was done in attempt to lower FEXT for the highest frequencies. Coincidentally, the cable performed marginally (still within standards, of course) around
100MHz range, but brilliantly above approx 185MHz all the way to 250MHz.I would even speculate as far as to that CAT6 components are tuned by their manufacturers to perform better at very high frequencies because it looks great in the data sheets and marketing materials. However, since no applications are actually working at above 100MHz so far, any CAT6 performance improvement claim should be taken very skeptically.
The purpose of this post was not to trash CAT6 standard, I repeat: it was not to trash CAT6 standard! ;-) Kudos to my beloved customers with CAT6 cabling systems installed between 1999-2004!
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