History and Organisation of Structured Cabling Standards
the beginning there were mainframe computers, made by companies like IBM,
Sperry, Univac and Burroughs. Each
computer had cables specifically designed for that computer and its peripherals,
e.g. IBM Bus & Tag.
didn’t change much until the arrival of Local Area Networks, LANs, which were
defined by agreed and open standards in the 1980s. For the first time datacommunications equipment from
different manufacturers could be expected to communicate with each other.
The first LAN to be universally accepted was Ethernet.
This was defined by the Institute of Electrical and Electronic Engineers,
the IEEE, within their 802.3 committee. The
first version of Ethernet was 10Base5, designed to offer a 10 Mb/s shared bus
using a 50 ohm coaxial cable. Shortly
after came thinnet/cheapernet, which used a smaller coax cable, and was titled
1984, IBM introduced the concept of structured cabling whereby a common set of
cables and connectors were installed to wherever people would be presumed to be
sitting at some time in the future. This
was also called flood wiring and is the same concept as ordinary telephone
extensions. Before that cables
linking mainframes to peripherals were only added as and when necessary.
This made moves and changes very expensive.
IBM cabling system was based on a two pair screened 150 ohm cable with a
dedicated universal connector. This
product was paralleled by the development of the IBM Token Ring 4 Mb/s LAN which
was intended to operate over the IBM cabling System.
in the ‘80s, AT&T introduced a cabling system based on standard American
telephone components, these being 100 ohm, 4-pair unscreened cable, a
cross-connect system based on the 110 Insulation Displacement Connector and
8-wire connector known by its USOC designation as the RJ45.
This is still the basis of most structured cabling systems available
the beginning of the 1990s, cabling systems were still
manufacturer specific, Ethernet was still based on coax.
This changed with the arrival of the 10BaseT standard,
whereby Ethernet could now run over 4-pair, 100 cable.
The market really opened up at this stage with
many new entrants arriving on the scene.
With no other standards other than 10BaseT however
many customers were becoming very confused by competing
performance claims from cabling manufacturers.
Anixter introduced a concept of grading cables
into levels, as an aid to both purchasing and selling
Level 1 was basic telephone cable and level 3 was
the best, 16 MHz grade, for 10BaseT.
in the early 1990s, standards writing bodies started to
pick up on the rapidly expanding world of structured cabling.
ANSI, the American National Standards Institute
asked the Telecommunications Industry Association, the
TIA, and the Electronic Industries Alliance, the EIA to
write national standards.
The TIA changed Levels to Categories and Category
3 was born. This
was closely followed by Category 4 when IBM declared that
they needed a 20 MHz bandwidth for their new 16 Mb/s Token
Ring LAN. The
cabling standard from the TIA/EIA became TIA/EIA 568.
the Organisation for International Standards produced
ISO 11801 and CENELEC produced EN 50173 for the European
4 had a working life of less than a year after system
designers made it clear that 100 Mb/s LANs were on the
way, and Category 5 specified to 100 MHz was introduced.
The major standards i.e. TIA/EIA 568A, ISO 11801
and EN 50173 were finally published in 1995, and lasted
substantially intact until 1999/2000, when the advent
of gigabit Ethernet (IEEE 802.3ab) forced the introduction
of enhanced Category 5.
In 2001/2 we saw the publication of Category 6
(a 250 MHz system) and Category 7, a 600 MHz system.
Standards now cover many different aspects of the
premises cabling business. These
Cable System Design
Earthing, Grounding and Bonding
Cable Containment and Administration
Directives and Codes, particularly in Europe, America,
Canada and Australia
Local Area Network Standards
European standards of interest come under CENELEC, which is based in Belgium and
set up in 1973 as the officially recognised European standards organisation by
the European Commission in Directive 83/189. CENELEC standards are called European Norms or ENs.
Standards not yet published are called preliminary European Norms or
European country still maintains its own national standards body, such as the
British Standards Institute in the UK, but CENELEC standards are adopted as
national standards where they exist and then, for example, in the UK, ‘BS’
is placed in front of the ‘EN’ number.
There are some exceptions, such as BS 7718 The Code of Practice for Fibre Optic Cabling, which has no
the UK the Fibre Industry Association initiated the BS 7718
Code of Practice.
The IEE, Institute of Electrical Engineers writes
the nationally accepted Wiring Regulations (also known as
BS 7671), which contains safety issues of power cabling,
earthing, bonding etc.
OFTEL was the British ‘Office of Fair Trading
for the Telecommunications Industry’.
Their charter stated that they were the:
‘……..independent regulatory body
with responsibility for ensuring that holders of telecommunications licences
comply with their licence conditions. OFTEL
maintains and promotes effective competition in the telecommunications industry
and promotes the interest of consumers and purchasers of telecommunications
services and apparatus in respect of prices, quality and variety.’
interest in structured cabling was limited to the maintenance
of telephone cabling and the approval of electronic equipment
which may be connected to national telecommunications networks.
Such approval must first be sought from BABT, the
British Approvals Board for Telecommunications.
OFTEL provided a wiring code and this is addressed
in British Standards publication ‘A Guide to Cabling in
Private Telecommunications Systems’
DISC PD1002. There is input to this document from the Telecommunications
Industry Association, the British trade association for
the telecommunications industry and not to be confused with
the American organisation of a similar name. OFTEL was absorbed
general, European Union bodies spending large summs of public
money should use CENELEC standards, where they exist, to
specify their requirements to ensure fair access to that
market by all European manufacturers.
is another European body that works in partnership with CENELEC and ETSI.
CEN’s mission is, ‘to promote voluntary technical harmonisation in
Europe in conjunction with world-wide bodies and its partners in Europe.’
is the European Telecommunications Standards Institute in Southern France.
It produces voluntary telecommunications standards in response to
requests from its members, currently numbering 700 across fifty countries.