© Copyright Brian Brown, 1996-1999. All rights reserved.
This material may not be reproduced in printed or electronic
format without the express permission of the author.
| EIA/TIA
| Category's
| EIA/TIA-568A
| EIA/TIA-568B |
| 10BaseT
| 10BaseT Wiring
| 100BaseFX
| 100BaseT4 |
EIA/TIA-568 WIRING STANDARD
This standard
defined in July of 1991, specifies a cabling system,
which is vendor independent (does not care what is attached to it)
and capable of lasting ten years.
The latest version is 568B, which contains some enhancements to
the original standard.
The standard specifies SIX subsystem
components of the cable system,
- Entrance Facility
This is the area where outside cabling interfaces with the buildings
cabling system. This is typically a secure room. Often this area is
considered a demarcation area, where the Internet Service Provider
(ISP) or Telecommunications provider's
responsibility ends and the building owners begin.
- Equipment Room
This room houses the Private Automatic Branch Exchange (PABX a system which
implements a local internal telephone system for a company) unit, modems,
routers, network hubs and
sometimes servers.
It is possible to also provide the facilities of a telecommunications
closet, and also be located in the Entrance Facility. It should be secured,
have adequate ventilation, power and space for equipment racks.
- BackBone Cabling
The backbone cable connects the telecommunications closets to the equipment
room and entrance facility. This is wired in a star topology. The four media
options for backbone cabling are,
- 100-ohm unshielded twisted pair (not exceeding 800 meters)
- 150-ohm shielded twisted pair (not exceeding 700 meters)
- 50-ohm coaxial cable (not exceeding 500 meters)
- 62.5/125um multi-mode fiber (not exceeding 2,000 meters)
- Telecommunications Closet (TC)
This is a room which houses only telecommunications cabling system equipment,
such as cross-connect patch panels for the horizontal and backbone wiring
system. It may also contain hubs or
switches. There is often one or more
TC's per floor.
- Horizontal Cabling
The horizontal cable extends from the TC to the wall outlet in the users
work area. There are FOUR media options for horizontal wiring
- four pair 100-ohm UTP
- two pair 150-ohm STP
- 50-ohm coaxial cable
- two-fiber 62.5/125um fiber
All horizontal cabling is implemented using a star topology, and must
not exceed 90 meters from the TC to the wall outlet. A minimum of TWO
outlets are required per work area, one of which must be wired with
four-pair 100-ohm UTP cable.
The color coding of the UTP cable is,
- pair 1: white-blue and blue
- pair 2: white-orange and orange
- pair 3: white-green and green
- pair 4: white-brown and brown
- Work Area
This is where the user is located. Patch cables connect the users equipment
(such as phone, fax, computer) to the wall outlet.
The standard also specifies the use of an eight-pin modular RJ-45 jack for
wall outlets using Unshielded Twisted Pair (UTP).
Categories of UTP Cabling
The EIA/TIA standard specifies FIVE categories of UTP cabling
- Category 1
uses 22 or 24 AWG (American Wire Gauge Standard) solid wire and is not suitable for data transmission
- Category 2
uses 22 or 24 AWG solid wire, used for PABX and alarm systems, and
has a maximum bandwidth of 1Mhz
- Category 3
uses 24 AWG solid wire having an impedance of 100 ohms with a
maximum bandwidth of 16Mhz
- Category 4
same as Category 3 but rated to 20Mhz
- Category 5
uses 22 or 24 AWG pair wire having an impedance of 100 ohms with
a maximum bandwidth of 100Mhz, typically using an RJ45 connector
and used to implement 10BaseT
EIA/TIA-568A Connector Specifications
This is gradually being phased out in favour of EIA/TIA-568B