Broadband Explained

What is it ?

“Broadband” is the commonly used name for a means of providing High Speed internet connectivity over a standard phone line.

Its correct name is “Asymmetric Digital Subscriber Line”, or ADSL.

The “asymmetric” in the name relates to the fact that generally, the “download” speed of data, that is, data “coming to you” is faster than the “upload” speed (going away from you”. There is in fact an “SDSL”, which is Symmetric, where the download and upload data speeds are the same – but SDSL is only provided on dedicated lines – and not on standard phone lines. SDSL thus falls outside of the general subject of broadband in this discussion.

Broadband technology used over a standard phone line enables an internet connection to be established without affecting the normal “telephony” use of the telephone line. This means that, unlike earlier “modem” type connections, you can use the telephone or a fax machine etc whilst the internet connection is in use.

Historically, traditional dialup modems, and ISDN connections gave connection speeds between 40-56 Kilobits per second (Kb/s) for modems, and 64/128 Kb/s for ISDN. Broadband download connect speeds, by comparison are much, much quicker than this. – in most cases typically 40 (2Mb/s) to 160 (8Mb/s) times faster than a dialup modem.

The actual download speed you will get depends on the length of your phone line from the telephone exchange (The upload speed is much slower, at 250Kb/s or 440 Kb/s in the case of 8Mb or ADSL+ broadband – and is usually unaffected by the telephone line characteristics as described below) Expected download speeds vary because: as the broadband “signal” passes over the phone line from the telephone exchange to you - it gets weaker in signal strength, and results in a lowering of the broadband “data rate” (known as the “synchronization” or “sync” rate). This sync rate can be seen in most ADSL modem setup menus as the “connect” speed.

Most broadband internet packages are sold at a “monthly fixed cost”, and because broadband and telephony can be used together, there is no need to regularly “disconnect” from the internet as one used to do in the days of dial up modems. This means that the internet connection can be left “always on”, and so, combined with the typically high speed of connection – makes the internet connection much more useful, with a wide range of applications, from much quicker web surfing – to downloading audio and video content in real time – and more recently – using the internet connection to support telephone calls – known as “VOIP” – or Voice over Internet Protocol”.

So: Broadband describes a permanent type of internet connection that enables much larger large amounts of data to be exchanged in a much shorter time than was able to be obtained originally with a modem or ISDN type connection.

The "band" in "broadband" refers to bandwidth which is a measure of the amount of information in a given amount of time that can be carried by a connection. That is why people talk of “so many bytes or kilobytes per second”. On older dialup modems, the capacity of the connection was at best 56k, i.e.: 56 kilobits per second (This is considered in this context as a "narrowband" connection, as it transfers relatively little data per second). Broadband download connections surpass this rate of information transfer considerably. Broadband enables download data transfer at a rate of **up to 8Mbits per second (almost 160 times faster than a 56K modem connection). ** depends on type of ADSL service, and length /quality of phone line.


There are additional limiting factors (apart from the effect of a long phone line as described earlier) to the actual data “speed” of any broadband connection, and a major one is “Contention”. This is explained below:
The broadband connection to your computer or terminal is not unique to you. It is effectively shared between you and up to potentially 49 other users (50:1 contention) in domestic grade broadband, and 19 other users (20:1 contention) in business grade broadband This means that there is a probability at any given time that there are others using the 'same' connection as you, and in that case the data 'flow' is shared between all of you. This means that a reduction in effective data speed is evident. The “probability” however of many people accessing data at precisely the same time as you will generally be low, and therefore in most cases you will still get a very significant speed advantage over a modem or ISDN type connection. Also – you can now see that “business grade” broadband is 2 ½ times better than domestic grade in terms of contention or “sharing” – and that is a major reason why it’s more expensive –as it effectively serves less people per overall “connection”!

So in summary, broadband delivers information much more quickly, brings you the Internet 'on tap', and lets you use the connection for multiple, simultaneous tasks. And you don't pay by the minute - a fixed monthly rate applies.

There are other Major benefits that become apparent when considering broadband. Internet services are rapidly growing in popularity and it's not just about looking at web pages, downloading movie clips or email. For example, a company can store all of the data that normally would have been kept on local drives and servers onto a secure central server, which is then accessed at speed over the Internet. That is: you are now using the Internet to provide you with a very convenient 'network'. Your documents are available to you wherever you are, whatever hardware you are using - and you will still have simultaneous access to all the other applications over the Internet. As a result, employees and customers can access information more readily, and intranets and corporate portals allow you to do business more effectively. Everything becomes more interactive! Updating your website is far more efficient so your site is not offline for hours as the new information uploads. Data transfer is swift and the capabilities of broadband become more and more important as we begin to work remotely over the web.

Installation Requirements

In order to benefit from Broadband you need a Standard BT Analogue Telephone line, from an ADSL-enabled exchange (most exchanges are now enabled)

Placing a broadband order with us is easy. Just give us your phone number, address and post code – (and a Migration Authority Code from your present broadband supplier if you are already on broadband with someone else) and we do the rest. We will test your phone line so you will know in advance what connect speed you can expect.

All the installation work on your phone line is done at the exchange, and all you need to do is install the pre-configured modem and associated micro filter, which we provide.

If there are special circumstances with your internal telephone line installation – such as several internal extension telephone points, noise pickup from other electrical or electronic equipment affecting the quality and speed of your broadband connection – we can attend your premises for specialist testing, and installation.

We only provide “Ethernet” or “LAN” type ADSL modems. / modem routers

These types of Modem use the “local area network” (LAN) port of your pc, (unlike USB types), and are much more robust, and secure, than their USB counterparts. They don’t require any software to be installed on your Pc – and they use the internet facilities supplied as standard within the PC operating system such as Microsoft Internet Explorer for websurfing, and Outlook Express, or Outlook for emails. You can of course use any other internet client software if you have a preference.

Because the Ethernet type modems are separately powered, and perform the “broadband internet connection” function completely independently from your PC - they are much more stable in operation, and have the inherent ability to provide additional Firewall security, and can easily be substituted for wired or wireless router types enabling multiple user access – and the ability to create your own local area network.

For further information – or to order broadband from the professionals – please give us a call on 0845 331 1003