Broadband Speeds Over Cable and Telephone Lines
The internet is now ubiquitous and for those lucky enough to have access to cable services the cheap cable and internet packages that are available on the market today mean that most people can easily afford fast broadband along with their favourite television channels. Of course there are still large numbers of people who can’t access cable and although their numbers are declining, it could be many years before cable is available to the whole population of the UK.
Fortunately for the majority of them, recent innovations in ADSL mean that, although they are unable to enjoy the superfast broadband services that are available on cable, they can still receive reasonably fast broadband. If you compare broadband speeds that are available on cable with those that are available over standard telephone lines, some of the lower priced cable broadband packages offer the same sort of speeds as the higher end ADSL packages. Typically cable broadband speeds start at around 30 Mbps (megabits per second) and the higher end ADSL speeds can be up to 25 Mbps.
However, for those looking for the higher end cable broadband packages, speeds of up to 100 Mbps are currently available and speeds up to 200 Mbps will be rolled out in the not too distant future. This is well above the maximum currently available over ADSL, but new innovations in that field could mean that in the future it may not be left quite so far behind as it is today.
The problem in supplying fast broadband over telephone lines relates to the amount of interference that occurs between telephone lines. The higher the frequency that is used to transmit the signal, the greater is the interference. The current ADSL technology is ADSL2+, and its broadband speed limit is around 25 Mbps, but there is a more advanced technology called VHDSL, which stands for Very-high-bit-rate digital subscriber line. In its second generation VHDSL2, this technology is capable of broadband speeds of 100 Mbps, roughly the same as cable. However the maximum distance over which the data can be transmitted at this speed is 300 meters, though already 40 Mbps VDSL services are being made available in certain areas. The technology is mostly used in conjunction for cable. Cable provides broadband to terminals and VHSDL2 provides the final link between the terminal and the user; this is called the final mile.
The latest development in VHDSL2 is called vectoring and is essentially a noise cancellation technique. It is still fairly experimental but it can potentially achieve 100 Mbps and maybe even faster speeds; already 300 Mbps has been demonstrated over short distances.
It will always be expensive and commercially uneconomic to supply users in the more rural locations with cable; however this does not mean that a two speed internet economy is inevitable. Telephone lines are already in place and technologies are being developed that can boost data speeds far beyond those that are available currently. Perhaps in the future rural dwellers will be served by a hybrid service which is partially cable and partially copper.
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