Moray.book Page 22 Wednesday, December 18, 2002 3:00 PM
Specifications
Cables
Twisted-Pair
Port Type
Cable Specifications
Maximum Length
10 Mbps Operation
Category 3, 4, or 5 100-ohm differential unshielded twisted-pair
100 meters
(UTP) or shielded twisted-pair (STP) cable, complying with IEEE
802.3 10Base-T specifications, fitted with RJ-45 connectors
100 Mbps Operation
Category 5 100-ohm differential UTP or STP cable, complying
100 meters
with IEEE 802.3u 100Base-TX specifications, fitted with RJ-45
connectors
1000 Mbps Operation
Category 5E 100-ohm differential UTP or STP cable, complying
100 meters
with IEEE 802.3ab 1000Base-T specifications, fitted with RJ-45
connectors
(please see “Note on 1000Base-T Cable Requirements”, below)
Note on 1000Base-T Cable Requirements.
The Category 5 networking
cables that work for 100Base-TX connections should also work for
1000Base-T, but for the most robust connections you should use cabling that
complies with the Category 5E specifications, as described in Addendum 5 to
the TIA-568-A standard (ANSI/TIA/EIA-568-A-5).
Because of the increased speed provided by 1000Base-T (Gigabit-T), network
cable quality is more important than for either 10Base-T or 100Base-TX.
Cabling plants being used to carry 1000Base-T networking must comply with
the IEEE 802.3ab standards. In particular, the cabling must pass tests for
Attenuation, Near-End Crosstalk (NEXT), and Far-End Crosstalk (FEXT).
Additionally, unlike the cables for 100Base-TX, the 1000Base-T cables must
pass tests for Equal-Level Far-End Crosstalk (ELFEXT), Multiple Disturber
ELFEXT, and Return Loss.
When testing your cabling, be sure to include the patch cables that connect
the switch and other end devices to the patch panels on your site. The patch
cables are frequently overlooked when testing cable and they must also
comply with the cabling standards.
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