HISTORY OF THE EIA/TIA-568 STANDARD: At the beginning of 1985, companies representing the telecommunications and computer industries were concerned with the lack of a standard for building telecommunications wiring systems. The Computer Communications Industry Association (CCIA) requested that the Electronics Industries Association (EIA) develop this necessary standard. Six years in the making, the EIA/TIA 568 Commercial Building Telecommunications Wiring Standard is the result of their efforts. Published in July of 1991, the EIA/TIA 568 standard serves the following purposes:
This lesson is meant a s a reference sourc tha highlights the key points of the EIA/TIA-568 Standard and its soon-to-be-revised version. The long- awaited revision to the standard is expected to be completed sometime in 1994.Whenever this lesson cites anticipated changes from the revised standard,those changes appear as *italics.
This lesson is not intended as a substitute for the original document. For a further discussion of any topic in this guide, please refer to the actual EIA/TIA-568 Standard.
Building entrance facilities provide the point at which outside cabling interfaces with the intra-building backbone cabling. The physical requirements of the network interface are defined in the EIA/TIA-569 Standard.
The design aspects of the equipment room are specified in the EIA/TIA 569 standard. Equipment rooms usually house equipment of higher complexity than do telecommunication closets. Any or all of the functions of a telecommunications closet may be provided by an equipment room.
(specified Topology: Hierarchical Star)
Backbone cabling runs between telecommunications closets, equipment rooms, and entrannce facilities (main cross-connects) within the telecommunications cabling system infrastructure.
Four media typed are recognized as options for backbone cabling with maximum distances as follows:
A telecommunications closet is the area within a building that houses the telecommunications cabling system equipment. this includes the mechanical terminations and/or cross-connect for the horizontal and backbone cabling system. Please refer to EIA/TIA-569 for the design specifications of the telecommunications closet.
The horizontal cabling system extends from the work area telecommunications (information) outlet to the telecommunications closet and consists of the following:
Three *media types are recognized as options for horizontal cabling, each extending a maximum distance of 90 meters:
*The next revision of the EIA/TIA-568 Standard will not recognize coaxial cable as a cabling choice, even though it does appear in the current 568 document.
The work area componets extend from the telecommunications (information) outlet to the station equipment. Work area wiring is designed to be relatively simple to interconnect so that moves, adds and changes are easily managed.
Work Area components
Two ports minimum
In addition to the 90 meters of horizontal cable, a total of 10 meters is allowed for work area and telecommunications closet patch and jumper cables.
As ransmission rates have increased, higher performance UTP cabling has become a necessity. In addition, some means of classifying horizontal UTP cables and connection hardare by perfomance capability had to be established. These capabilities have been broken down to a series of categoreis as follows:
Characteristic Impedance of hroizonal categorized cables = 100 ohms + 15% from 1 MHz to the highest referenced frequency at a paricular category (16, 20. or 100 MHz).