Information Technology Reference
In-Depth Information
Telecommunications Cabling Standard, Part 3: Optical Fiber Cabling Components
Standard
. The C revision basically incorporates the technology within TIA-568-B, plus all
of the addenda and the applicable telecommunications standards bulletins (TSBs) that
were approved at the time of the draft final vote.
The new structure allows the specifications for the wiring components to be com-
pletely separate from the general structured guidelines. It also allows each section to
be separately revised and additional sections to be added as necessary.
Some of the New Changes in 568-B and -C:
■
Divides the standard into three sections (-B) or four sections (-C), with separate
draft and ratification processes.
Replaces “telecommunications closet” with “telecommunications room.”
■
Defines performance specifications for Category 6, Augmented Category 6 (AC6),
and 5e balanced 100-ohm cabling (keeps Category 3 and drops reference to
Categories 4 and 5, in favor of Category 5e).
■
Adds specifications for Category 7, 4-pair, individually foil-shielded, balanced copper
cabling.
■
Incorporates provisions for IEEE 802.3af DTE Power via MDI (commonly referred
to as “Power over Ethernet”, or PoE).
■
Defines performance specifications for 50/125 µm optical-fiber cables (in addi-
tion to the 62.5/125 µm cables).
■
Allows alternative fiber connector designs in addition to 568-SC (such as the new
SFF, small-form factor, fiber connectors).
■
Adds many performance parameters for copper cabling, including such things as
attenuation-to-crosstalk ratio (ACR), delay-skew, power-sum near-end crosstalk
(PSNEXT), and far-end crosstalk (FEXT and ELFEXT), and alien ELFEXT (ANEXT),
which is crosstalk induced by unwanted coupling from a neighboring pair and is
needed to accommodate 10-Gb speeds.
■
TIA-568 Cabling Options
The TIA-568-C cabling system actually includes four types of cable options:
unshielded twisted-pair (UTP), shielded twisted-pair (STP), multimode 50/125 and
62.5/125 optical fiber, and single-mode fiber (50-ohm coax is grandfathered for
existing installations only). See Chapter 11 for a discussion of fiber-optic cabling.
TIA-568 Component Categories
TIA-568-C cabling combines the low cost of modular wiring connections and
twisted-pair cable with a system of performance classifications and installation pro-
