Until recently, Category 5 data cabling was considered adequate for typical installations. Now Category 5e and Category 6, with their data transmission rates of up to 1GB, may be superseded by Category 7 - or even Category 8. So what should installers recommended for their customers? Mike Stevens reports.
Like computer power and memory, the demand for data transmission capacity and speed has risen exponentially in recent years. Attempting to look ahead and determine with confidence the necessary bandwidth and data rate for the office of the future is becoming more difficult as the pace of changes increases.
The demise of copper in favour of high capacity fibre optic cable has been predicted before, but advanced versions of traditional unshielded twisted pair (UTP) copper cable have so far kept pace with today's information technology.
Even if they accept that data networks in buildings can be constructed with copper for the foreseeable future, installers should be learning about fibre installations. Building a large network, linking a building to an external data highway or to other buildings, or linking horizontal networks on each floor of a building to a vertical data trunk will almost certainly involve terminating fibre optic cables.

Categorical confusion

Although a Category 7 cabling standard may be coming, designers have three choices at present: Category 5e (enhanced Category 5), Category 6 copper cabling, or fibre optic to the desktop.
Category 5e is a specification designed for data networks that support high speed data transmission, like Gigabit Ethernet, but keeping the signalling frequency to 100MHz. Category 5e has replaced the 100MB Category 5 as the baseline network.
To achieve this tenfold increase in capacity, all four pairs in the cable are transmitting and receiving data simultaneously, so the cabling specification has been changed to more tightly control the cabling infrastructure. Also, the performance of transmitting and receiving devices has been improved using complex coding techniques.
If a data rate of 1GB to the desktop covers the user's foreseeable data needs, Category 5e is an adequate installation standard. If, however, the user anticipates higher data rates, designers should consider Category 6 or possibly fibre.
Category 6 is a specification for data cabling that supports 1GB data transmission at a frequency of 250MHz. This provides an excellent platform for Gigabit Ethernet with increased margins or "headroom" over Cat 5e, and also caters for future high speed data transmission protocols with evenhigher data rates.
"The decision on whether to use Category 5e or Category 6 currently depends on the price sensitivity of the installations," says Richard Ednay, technical director at data cabling training firm Optical Technology Training (OTT) of Skipton in North Yorkshire.
"Category 5e offers a cost-effective installation for Gigabit Ethernet, whereas Category 6 gives a safety margin but adds cost and complexity to the installation. As data rates increase, there is less margin for error and any deficiencies in the installation will show up in an increased likelihood of failure when the cable is tested."

Easy move

For installers familiar with the old Category 5, it's easy to make the move to Category 5e, but Category 6 places increased demands on the installer.
"Category 5e is quicker, easier and cheaper to install than Category 6, though the margin between the two systems is decreasing all the time," says David Stefanowicz, technical manager of ITEC, the Electrical Contractors' Association's data cabling group. "Category 6 is less tolerant of abuse and so is more expensive to install and maintain."
The proposed Category 7 will involve the use of shielded rather than unshielded twisted pair copper cabling. The switch will help achieve data rates of over 1GB.
"Category 7 cabling for data rates of up to 10GB is quite a different cable, as each of the four pairs of cable and the whole cable are shielded," says Ednay. "Some argue this is typically Germanic over-engineering, and it is Germany and Austria that are the main marketplaces for Category 7 cabling."
Some argue that installing fibre is the only way to future-proof an office currently being fitted with a network.
With 1GB Ethernet now considered standard technology, there are predictions that 10GB transmission rates will be required as early as 2005 as video conferencing and electronic transfer of large files such as CAD drawings become commonplace. With many users aiming for a five-year cycle of upgrades for IT hardware, this would leave any IT manager installing a 1GB system now facing a complete replacement in less than half that time.
It is relatively cheap and causes little disruption to upgrade the vertical part of a building network, but installing new horizontal cabling from the trunk to each desktop is expensive and highly disruptive.

Fibre to desktop

Proponents of fibre to the desktop points out that, despite the advances in signalling technology that have allowed data rates over copper to rise from 10Mb to 100MB and now to 1GB, there are intrinsic limitations on the capacity of copper cabling. As data rates begin to approach 10GB, the cost of the transmission equipment will begin to rise rapidly and the transmission distances possible fall equally rapidly. If so, multi-mode fibre optic cables could become more cost effective than copper for horizontal networks.
While there are specific health and safety concerns about cleaving and splicing fibre optic cables, the techniques involved are straightforward given the right training and equipment. Specialist fusion splicing and testing equipment used to be prohibitively expensive, but the cost has fallen rapidly in recent years to put it within reach of most installers.
As data transmission rates inexorably rise, the complexity of data cabling and the pressure of installers to improve the quality of installations will increase. As a result, proper training will become even more important for contractors moving into the market or installers familiar with Category 5.
Rather than tying in with proprietary system vendors, OTT recommends independent training such as the five-day City & Guilds courses - 3466-04 for copper cabling or 3466-02 for fibre optic systems.
"City & Guilds 3466 provides generic skills so installers really understand what they are doing," says Ednay. "City & Guilds also includes a formal assessment, so it gives the installer more credibility."

Competency levels

The good news for clients is that ECA ITEC has led the industry to develop competence based on the New European IT Cabling Standards and UK law. These new competency levels are backed by NVQs being developed by NET in structured cabling. There should soon be modern apprenticeships in structured cabling, ensuring that next generation IT systems are supported by a competent workforce.
The ECA is the UK's representative body at the European Telecommunication Services Association (ETSA), and it has aligned its company qualifications for the highest categories of ITEC members with the ETSA quality standard Qualifcom. Non-ECA members that comply with the ETSA's Qualifcom standard can also become ETSA approved installers by undergoing an inspection by the ECA.
The ECA's ITEC group is now 300 strong, though Stefanowicz estimates that as many as 70% of the ECA's 2,200 members install data cabling.
While the data communications market has fallen back from the peaks of 2000-01, the natural life of an installation is around five years and falling. So with another surge in demand forecast for 2004-05, installers should start acquiring the qualifications and experience they will need to take advantage of this opportunity.