Future proof

Ken Hodge, of global cabling and data solutions company Brand-Rex, provides a guide to in-building LAN media, the factors to be considered and how to select a system

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Future proof
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By  Ken Hodge Published  March 18, 2010 Network Middle East Logo

Specifying a structured cabling system is a business-critical decision. A vital utility with a lifecycle of possibly 15+ years, it represents a major capital investment. The chosen infrastructure will need to support a wide array of network services for both current and future applications, as well as complying with environmental and regulatory demands.

Compliance with international standards and local regulations is essential when commissioning a new network. To provide a seamless transmission network, LAN media must comply with standards that ensure interoperability and optimum performance. The volume of specifications should not be underestimated, and those listed in Table 1 and set out by the International Standards Organisation (ISO), International Electro-technical Commission (IEC) should be your first port of call.

A standard or code of practice is widely regarded as the approved mode of compliance and the wording used is extremely precise. Verifiable requirements are denoted by the use of ‘shall'/'shall not', ‘it is essential that', and ‘under no circumstances', and their interpretation is detailed in the Standards guides.

LAN media and drive distances

LAN media comprises three transmission mediums - copper, fibre and wireless. Each has characteristics suited for particular situations, with selection governed by several factors:

  • Performance - as described in ISO/IEC 11801

  • Environment - as set-out within the ISO/IEC 11801, 24702, 15018 or 24764 specifications for system design

  • Efficiency

  • Cost

  • Ease of installation, operation and maintenance

  • Availability

  • Distance covered


There are two basic types of copper cabling: twisted-pair and/or twin-axial twisted cables (‘balanced' cabling); and coaxial cable (‘un-balanced' cabling), which has a centre conductor of copper wire and an outer concentric conductor. Primarily used in LAN applications, twisted-pair copper cabling is designed to provide a 100-metre length transmission line and comes in either shielded or un-shielded (UTP) forms.

Rated by performance class, Category 5 (Cat5), Cat6 and Cat6A products are RJ45 connectivity-based, fully interoperable and backwards compatible. Meanwhile, Cat7 and 7A products are backwards compatible to lower classes using hybrid cords.

Copper cabling classification:

  • Class D - rated to 100MHz, uses Cat5e components and supports Ethernet, Fast Ethernet, Gigabit Ethernet, PoE and ATM

  • Class E - characterised to 250MHz, employs Cat6 components and supports Class D and ATM1200

  • Class EA - a 500MHz system using Cat6A components developed for transmission of 10GBASE-T

  • Class F and Class FA systems - rated to 600Mhz and 1GHz, use Cat7 and Cat7A components respectively, and are designed to distribute multiple services in a building and terminate to RJ45 connectivity via hybrid cords

Traditionally, UTP was favoured in the UK for Class D and Class E systems because it was smaller, lighter and more flexible, making it simpler to install than screened cabling. However, with ClassEA the reverse is true, while screened cabling also provides a higher degree of immunity to EMI, making it a preferred option for critical areas of the network (e.g. data centres).

Inside buildings, cables with an LSZH-FR (Low Smoke Zero Halogen - Fire Resistant) sheath are strongly recommended. For installation, conduit runs can be in ceilings, walls or under floors, but use should be restricted to permanent workstation outlet locations. Plenum or dropped ceiling/raised floor runs are often the easiest to install, while cable trays or ‘ladder racks' provide a safe and efficient alternative.

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