What does it mean?

The word Broadband has become one of the most over used words in the english language. You see and hear it everywhere from magazines to TV. But what is it? The word itself doesn't really accurately describe anything but it has come to mean 'High-speed Internet Access".

In the early days of the Internet, people connected via over a standard phone line using a modem and that gave them, relative to today a slow channel to the web and email. The speed was low because the technology in use simply couldn't run any faster. The channel speed was limited by the equipment at each end and the lines it was running over. This technology is now referred to as Narrowband.

Then came the revolution. A new technology was invented that could send signals over the standard copper phone lines at much higher speeds. This came to be known as Broadband simply because it had a much higher capacity and speed than the old modem driven technology.

Broadband is a broad church

Broadband comes in many flavours. Most people use what is known as ADSL but Cable and 3G are also examples of broadband systems.

ADSL - Asymetric Digital Subscriber Line

Sounds complicated but we can keep it simple. The link between your computers and the Internet is divided into to streams - an upstream (from you to up to the internet) and a downstream (from the internet down to you). The clever bit is that the downstream channel is nice and wide the the upstream channel is quite narrow. The reason this makes sense is because most of the time you will be downloading from the Internet - receiving emails, looking at webpages, listening to music. The only time you really use the upstream is when sending a request to download something or sending out an email and these are usually very small. So that means we have an asymetric link. The DSL bit merely says that information is sent and received in digital format and you use a telephone line to as the physical connection.

ADSL Factoids

  • ADSL broadband is only available on a BT phone line
  • There is a multitude of broadband service providers for you to choose from.
  • The downstream speed you get depends on how far you are from the local BT exchange and that is measured a the copper travels not as the crow flies.The futher you are away the lower the speed.
  • Speeds vary from 512 Kilobits per second to 8Megabits per second


Many cities now have cable TV systems. The wiring is capable of carrying much more than just television signals. In fact it now carries telephone and internet too. This uses an entirely different technology that ADSL but the effect is much the same. The advantage of the cable system is that there is no asymetry in the channels, you get the same speed in both directions - in theory.

3G Broadband

The term 3G refers to Third Generation mobile technology. This is a high speed service that runs over the mobile phone network. It is typically used by people with laptops that want internet access on the move.


SDSL or Symetric Digital Subscriber Line is like ADSL but with both upstream and downstream channels having the same bandwidth and speed. This is a recent development and it is only available in certain areas.

Leased Line

The ultimate broadband services is something called a leased line. With this product an Internet Service Provider sets up a dedicated link between your premises and the internet. The service has guaranteed service levels and bandwidth and of course costs a lot of money. This is mainly used by medium and large companies to provided internet access for large numbers of users.

Relationship between telephones and broadband

This one is a real mystery to a lot of people but actually it's quite simple. Just think of the phone and internet broadband as two completely different products that delivered over a single line. Yes they can co-exist on the same piece of copper because of the magic of being on different frequencies.

So does that mean you can have one without the other? Well not quite. You can have the phone service without broadband but you cant have broadband without having the phone connected. Furthermore if you cancel a phone line because you dont need it any more the broadband service on that line will automatically be cancelled at the same time. So before you cancel phone lines in your company be sure to check that there is no broadband on that number. Once the cease process has been activated it cannot be stopped.

So lets say you accidentally ceased a phone line that had a broadband connection attached to it - what is the best way to get it switched on again? Sadly all you can do is wait for 5 working days while the cease completes then get you phone company to re-active the phone line and finally get the ISP to re-activate the broadband service - another 5 working days at least. I know - you think thats ridculous and it is but hey thats the system we have in th UK and it's not about to change any time soon.

Before you add or change a broadband or phone service - speak to you IT Support provider, they will make sure you dont make a costly mistake.



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