A revolutionary new technology has been announced which uses a previously overlooked method of using both wires in the copper twisted pair in order to double existing broadband speeds.
This new technology is an extension of the existing G.DMT standard, the form of modulation used on existing ADSL lines. Discrete Multi-Tone (DMT) modulation works by converting the digital data into a series of separate frequencies, or tones, that can be carried over telephone wire. More information on how DMT works can be found
here.
The new discovery, known as Advanced Frequency DMT (AF.DMT), relies on enhanced crosstalk-cancellation technology to allow the use of both wires in the twisted pair for the simultaneous transmission of data. This makes an existing phone line effectively capable of behaving like two separate lines.
"It's really quite simple," says Avril Jolly, a spokesperson for BT Research and Development. "Every telephone line consists of two wires, twisted together to form what is known as the 'pair'."
"The potential that this discovery brings to BT's 21CN rollout is very exciting, to say the least. I can't believe that something so simple has been overlooked for so long, and the fact that both wires in the copper pair could be used with the AF.DMT standard, to effectively double broadband speeds."
Trials of the new technology are expected to commence around the Milton Keynes and London Docklands areas later this month. Existing Fujitsu DSLAMs require a firmware upgrade to support AF.DMT connections. Ms Jolly also states that a nationwide firmware upgrade rollout implementation could be completed in as little as six months, although conclusive trials have yet to be completed. She also added that a number of incompatible DSLAMs in remote areas of the UK would require that the line cards be replaced with compatible dual-frequency cards which conform to the new standard.
A new type of ADSL modem is also required to make full use of the Advanced Frequency technology. BT have been working closely with Netgear to develop a prototype router, based on the popular DG834 series. This router, the DG834AF, utilises dual core technology, combining two Broadcom BCM6348 ADSL controllers on a modified system board design in order to support the AF.DMT standard. Simply put, the DG834AF is two modems in one box!
Kitz.co.uk has managed to obtain an exclusive photograph of the inside of this router, showing the two Broadcom chips side by side. |  New Dual-Core prototype router:
Netgear DG834AF |
We look forward to BT rolling out this new technology sooner rather than later. Because the infrastructure is already in place, all that is required is for the end user to purchase a new router, once the DSLAM modifications have taken place in the exchange.
It is to be hoped that this does not adversely affect BT's FTTC deployment schedule, as it is no substitute for VDSL2 over a short line. Whether AF technology can be combined with VDSL2 is unclear, but would certainly give BT a competitive edge over the Cable providers.
