250Meg broadband is the headline speed that is emerging from Australia. Dr John Papandriopoulos of Melbourne University has apparently managed to squeeze more capacity out of the standard copper telephone network by using algorithms that eliminate much of the interference.
There is not much more detail than can be found in the article on MacUser at present, due to the small matter of a pending patent application.
It seems the 250Mbps figure is the absolute maximum attainable, however a more realistic figure of 100Mbps is likely using the system. When you consider VDSL2 can already deliver 100Mbps at loop lengths of 0.5km and managing 50Mbps at 1km, it sounds less impressive. The 1km figure is very important as almost all phone lines are shorter than this when just the cable between the premises and street cabinet is considered. These new algorithms cannot change the physics that mean the signal travelling down the copper wire gets smaller the further it travels, but it can help us to get more from the little signal that does make it through.
The current copper twisted pair telephone networks have been in place in many countries for many decades and are all past their sell by date, but technology keeps finding ways to squeeze more out of them. The real question is when will companies like BT take the big leap and embrace fibre on a large scale to give them a local loop that will survive to the next century.