On 2/4/2012 6:53 AM, Camaleón wrote: > No, I can't see why is not that popular within the US, there are many > advantadges for having shielded cables because external interferences - > that are not always under your control- still apply (e.g., wireless > connections, proximity to high power lines or electrical equipments...) > whose effects can be properly minimized with cabling shielding.
These same effects are eliminated, in the US, by installation standards. These are are always under the control of the installer/contractor. There is no guess work involved and everything is predictable and "under your control". Wireless signals do not affect UTP ethernet cabling. Proximity to internal AC cabling, induction sources such as power distribution closets, AC motors, florescent lights, etc, is avoided during building construction or retrofit, because the cable plant is included in the architectural design, just like water pipes, sewer pipes, electrical conduit, etc. In the US, in the case of environments such as manufacturing floors etc with horrific EMI levels, fiber is used instead of UTP CAT5/6. With EFI levels that high, even STP won't save you. In summary, when installed correctly, UTP ethernet cable is superior to STP, due to the lower cost of the cable, connectors, and patch panels, and labor. Something worth mentioning is that over the past 10-12 years, a high percentage of new large office buildings and high rise apartments constructed in the US have had 100% fiber cable plants, no copper whatsoever, even including fiber into the cubicles. The only copper UTP in such facilities being patch cables from servers to core switches and between switch stacks. Note that datacenter copper is not part of the cable plant. "Cable plant" is the slang term for "structural cable installation", plant used as a verb, analogous to planting tomatoes in one's garden. Cost is one of the drivers. Today a 1000ft spool of 62.5/125 multimode fiber is equivalent or cheaper than CAT6a UTP. The installation labor is about the same as UTP. We'll continue to see more fiber to the desktop as the cost of copper continues to increase. The switch cost in an all fiber plant is higher per port due to the multimode transceivers, but not prohibitively so when purchased in volume. -- Stan -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/4f2d44f4.30...@hardwarefreak.com
