ANSI/TIA/EIA-568-A AND
ISO/IEC 11801
| ANSI/TIA/EIA-568-A |
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ISO/IEC
11801 |
| Commercial
Building Telecommunications Cabling Standard. The Telecommunications Industry Association (TIA) TR41.8.1
Working Group on telecommunications cabling published the ANSI/TIA/EIA-568-A standard in 1995. |
|
Information
Technology- Generic Cabling for Customer Premises. The International Organization for Standardization (ISO) SC 25/WG 3 Working Group on telecommunications cabling published the ISO/IEC 11801 standard in 1995. |
Following are highlights of the '568-A
standard and related Telecommunication Systems
Bulletins (TSBs) with notes on differences in
terminology and technical requirements with
respect to ISO/IEC 11801. For clarity and
consistency, '568-A based terminology is used in
the following overview.
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| Purpose |
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To specify a generic voice and data telecommunications cabling system that will support a multi-product, multi-vendor environment. |
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To provide direction for the design of telecommunications equipment and cabling products intended to serve commercial enterprises. |
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To enable the planning and installation of a structured cabling system for commercial buildings that is capable of supporting the diverse telecommunications needs of building occupants. |
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To establish performance and technical criteria for various types of cable and connecting hardware and for cabling system design and installation. |
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| Scope
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Specifications are intended for telecommunications
installation that are "office oriented".
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Requirements are for a structured cabling system
with a usable life in excess of 10 years.
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Specification addressed:
- Recognized Media - cable and connecting hardware
- Performance
- Topology
- Cabling Distances
- Installation Practices
- User Interface
- Channel Performance
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HORIZONTAL CABLING SYSTEM STRUCTURE
The horizontal cabling system extends from the
telecommunications outlet in the work area to the horizontal
cross-connect in the telecommunications closet. It includes the
telecommunications outlet, an optional consolidation point or
transition point connector, horizontal cable, and the mechanical
terminations and patch cords (or jumpers) that comprise the
horizontal cross-connect.
|
| (A) |
Customer
Premises Equipment |
| (B) |
HC
Equipment Cord |
| (C) |
Patchcords/cross-connect
jumpers used in the HC, including equipment
cables/cords, should not exceed 6m (20 ft.)
Note: ISO/IEC 11801
specifies a max. patchcord/cross-connect length of
5m (16.4 ft.), which does not include equipment
cables/cords. |
| (D) |
Horizontal
cable 90m (295 ft.) max. total |
| (E) |
TP or CP
(optional) |
| (F) |
Telecommunications
outlet/connector (TO) |
| (G) |
WA
Equipment cord
Note: An allowance
is made for WA equipment cords of 3m (9.8 ft.) |
Notes:
* An allowance of 10m (33 ft.) has been provided for
the combined length of patchcords/cross-connect
jumpers and equipment cables/cords in the HC,
including the WA equipment cords.
* In ISO/IEC 11801, the equivalent cabling element
to the horizontal cross-connect (HC) is called the
floor distributor (FD). |
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| Some
points specified for the horizontal cabling
subsystem include: |
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Application specific components shall not be
installed as part of the horizontal cabling.
When needed, they must be placed external to the
telecommunications outlet or horizontal
cross-connect (eg. splitters, baluns).
-
The proximity of horizontal cabling to sources
of electromagnetic interference (EMI) shall be
taken into account.
-
Recognized Horizontal Cables:
| 4-pair
100 Ohm unshielded twisted pair |
 |
| 2-fiber
(duplex) 62.5/125µm or a multimode optical
fiber (note: 50/125µm multimode fiber will
be allowed in '568-B) |
 |
| 2-pair 150
ohm STP-A |
 |
| *Note:
In addition, two alternate horizontal
cabling types allowed by ISO/IEC 11801 are
120 ohm unshielded twisted-pair and 50/125µm
multimode optical fiber. |
-
Multipair and multi-unit cables are
allowed, provided that they satisfy the
hybrid/bundled cable requirements of TIA/EIA-568-A-3.
-
Grounding must conform to applicable
building codes, as well as ANSI/TIA/EIA-607.
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-
A minimum of two telecommunications
outlets are required for each individual
work area.
First outlet: 100 ohm twisted-pair
Second outlet: 100 ohm twisted-pair, or
150 ohm STP-A, or 62.5/125µm multimode
fiber.
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Topology
The horizontal cabling shall be configured in a star
topology; each work area outlet is connected to a
horizontal cross-connect (HC) in a
telecommunications closet (TC).
TIA
Backbone Cable Distances (MC to HC)
Singlemode
Fiber.................................3000m
(9840 ft.)
62.5/125µm
Multimode Fiber.................2000m (6560
ft.)
UTP Copper
Applications < 5 MHz..........800m (2625
ft.) |
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| Some
points specified for the backbone cabling subsystem
include: |
|
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Equipment connections to backbone cabling
should be made with cable lengths of 30m (98
ft.) or less.
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The backbone cabling shall be configured in a
star topology. Each horizontal cross-connect is
connected directly to a main cross-connect or to
an intermediate cross-connect, then to a main
cross-connect.
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The backbone is limited to no more than two
hierarchical levels of cross-connects (main and
intermediate). No more than one cross-connect
may exist between a main and a horizontal
cross-connect and no more than three
cross-connects may exist between any two
horizontal cross-connects.
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A total maximum backbone distance of 90m (295
ft.) is specified for high band-width capability
over copper. This distance is for uninterrupted
backbone runs. (No intermediate cross-connect).
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The distance between the terminations in the
entrance facility and the main cross-connect
shall be documented and should be made available
to the service provider.
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Recognized media may be used individually or
in combination, as required by the installation.
Quantity of pairs and fibers needed in
individual backbone runs depends on the area
served. Recognized backbone cables are:
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Note:
50/125 µm multimode fiber will be recognized in
TIA-568-B.
- Multipair cable is allowed, provided that
it satisfies the power sum crosstalk
requirements.
- The proximity of backbone cabling to
sources of electromagnetic interference (EMI)
shall be taken into account.
- Cross-connects for different cable types
must be located in the same facilities
- Bridged taps are not allowed.
Notes: In ISO/IEC 11801, the equivalent
cabling elements to the main cross-connect (MC) and
intermediate cross-connect (IC) are called the
campus distributor (CD) and building distributor
(BD) respectively.
In addition to those listed, two alternate
backbone cabling types allowed by ISO/IEC are 120
ohm twisted-pair and 50/125 µm multimode optical
fiber.
50 ohm coaxial cabling is recognized by ‘568-A,
but is not recommended for new installations.
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