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10Gbps over 30 metres of copper? You might as well build FTTP

Tests have demonstrated that eyebrow-raising speeds of 10Gbps (10,000Mbps) are possible over copper telephone lines. 

That’s hundreds of times higher than the current top speed – 80Mbps – possible on BT’s FTTC (Fibre to the Cabinet) lines in the UK. 

As FTTC technology uses a copper line in the so-called ‘last mile’ – the connection between a broadband street cabinet and a customer’s home – the research has exciting implications for British broadband customers. But how useful will this actually be? 

A BT street cabinet, devoid of any next-gen superfast fibre
A BT street cabinet, devoid of any next-gen superfast fibre

The prototype XG-FAST technology is described as an extension of the G.fast tech – something which BT is testing out right now. 

G.fast promises to deliver download speeds of 1Gbps over FTTC lines over short distances – up to 250 metres – which opens up the possibility of faster speeds in inner city and suburban areas. In rural areas, where the copper last miles are longer, G.fast isn’t really viable. 

In a nutshell, XG-FAST is more of the same thing – technology that’ll vastly increase the top speeds possible with copper over short distances. Really short distances in fact. 

In order for 10Gbps to be possible over a bonded copper line (two lines fused together) a cabinet or node would have to be built within 30 meters of a customer’s property. 

Even then, these speeds have been demonstrated in lab conditions which according to Alcatel-Lucent’s table below, does not simulate a real-world environment where electromagnetic interference will have an impact on the speeds customers would actually get. 

Alcatel-Lucent’s trials also demonstrated symmetrical 1Gbps speeds – that’s 1Gbps download and upload speeds – over copper lines 70 meters long. 

This time, the company applied simulated interference applied to the line, so it’s perhaps a better indication of what XG-FAST could deliver in reality. 

As headline speeds and frequencies increase, the effective range decreases
As headline speeds and frequencies increase, the effective range decreases

These speeds are comparable to what customers can get over a full FTTP (Fibre to the Premises) line, which is fibre all the way to the home with no copper in the last mile. Subsequently, FTTP lines aren’t affected by interference and gigabit speeds are possible at distances of over 70 meters. 

Gigabit download and upload speeds are available right now from ISPs like Hyperoptic and Gigaclear and BT’s own FTTP network is capable of going as fast as 10Gbps – and possibly even faster – in the future. 

While XG-FAST promises speeds comparable to full fibre, it’s clearly not suitable for all parts of the country. In areas where fibre is being built so close to a property it might be cheaper for BT or whoever to simply connect the last mile instead. 

Judging by BT’s own prices, it’s not going to cost businesses much more in the scheme of things to build FTTP an extra 70 meters to a home. 

To upgrade from FTTC to FTTP on BT’s FoD (FTTP on Demand) programme, customers have to pay £3.50/metre depending on the length of your last mile – or £105 for 30 metres and £245 for 70 metres. 

XG-FAST is still in the prototype stages and so it won’t have any real impact on the market for some years to come. Even G.fast hasn’t been fully standardised yet – initial approval by the ITU (International Telecommunication Union) was granted in December 2013, but the first services which use this technology aren’t expected to arrive until next year at the earliest. 

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