Understanding ADSL

This page is part of the Business Advice Centre section of this web site - a selection of documents and files that are designed to help, guide and enlighten elements of Information Technology to those in business

This is a quick guide to help you understand the involvement & procedures of applying ADSL services in your organization or home. Prior knowledge of the benefits of ADSL and its speed capabilities is recommended before reading this guide. For ease the table below shows the standard common speeds in use today in 2002. If you presently use a standard modem or an ISDN connection for Internet & email you can see the increase in bandwidth or line speed that your modem sends & receives information. 

What is ADSL?

ADSL, or Asymmetric Digital Subscriber Line, technology allows the transmission of digital information at high-speed across existing copper telephone cable. The service is permanently available, so it is 'always on'. ADSL is a variant of DSL, the asymmetric part refers to the service using most of the available bandwidth downstream. The service is suitable for use by customers who expect to receive more data than they wish to transmit. The technology also supports analogue connection on the same line, which allows voice or fax calls to be made simultaneously.

How does ADSL work?

ADSL operates over a normal copper wire telephone line in areas where BT has enabled local telephone exchanges for high-speed ADSL data services. The ADSL signal is carried by two ADSL modems, one at the customer's premises and one at the local telephone exchange. The technology allows far greater data transmission rates than were possible in the past. A series of splitters (filters), one or more at the customer's premises and one at the BT telephone exchange, separate the analogue (telephone) signal from the ADSL signal. This means that telephone calls can be made at the same time that data is being sent or received.

British Telecom

As most people use BT for the standard phone lines the first place you are most likely to enquire about ADSL is with BT. This can be somewhat confusing as not only are they trying to aid your enquiry but they sell you their own ADSL solution, which to most people is normal as you may not completely understand your options. You should however be told that you can use someone else’s ADSL services and it is this that we make the comparison with Eclipse Networking services.

Eclipse Networking

ADSL services can come in several packages and Eclipse offer some of the best in the South West. One option is known as ‘Wires Only’ and as a business IT provider and support company, Somtech prefers this solution. The reason for this is because the installation is more customized for your network and Somtech’s support of Eclipse services has less cost attached to it due to the familiarity and partnership that both companies have. But you can find many companies throughout the UK that provide similar services.

How it is set-up

BT will usually rent the ADSL router to you on a monthly basis and usually configure the router for an IP address. (An IP address is a designated number much like a designated phone number). This address is determined by BT and not by your network requirements. Therefore, the long term cost can be more expensive. The best & most cost efficient way is to purchase an ADSL router out right and customize the IP address to your network or ISP IP address range.

Once this is avenue is decided you need to ensure that you have a standard analogue line that you can offer up to be converted to ADSL. Then you apply for the ‘Wires Only’ installation from Eclipse, which in short is purely the line conversion. The bandwidth or size of this line is also determined at this stage and is available from 512kbps to 2 MB’s. A set-up fee is paid to Eclipse, which Eclipse use to employ BT to set-up the ADSL line for you. See example below.

We will then provide at a reasonable cost an ADSL router which Somtech will configure on your behalf. Depending on how many PCs are connected to the internet on your network you can choose between the Connect Lite service (for up to 4 machines), or the Connect Service for a more resilient connection. The difference is down to the ‘contention’ rate which is governed by BT at the local Exchange. In layman’s terms ‘contention’ means how many users can use the ADSL line at any one time. The more users you have on the line the less performance each user receives. In the example of a 50:1 contention we can see here that the line is setup for 50 users and the less users or ‘contention’ you have the better the performance. It’s just like driving with different weights in your car. The more people you carry the heavier the load, resulting in a slower journey. Once decided you pay Eclipse a monthly fee for the desired connection size and rate. See example below.

Finally, you need the ADSL router to work on your local area network and pay BT line rental for the line dedicated for ADSL. Once in place the only monthly payment you need to make is ADSL services to Eclipse (excluding Web hosting & email) and the line rental to BT.

The example below is designed to show the order of events & uses the ‘ADSL 500 Lite’ service provided by Eclipse, which gives you 512kbps and has a contention of 50:1. Prices quoted are excluding vat & are correct at time of printing. 

• First you determine the size & ratio of an ADSL line you require. Advice can be given by Somtech if you are unsure
• You contact BT on 150 (Business Customers) and ask for a new analogue line or convert your ISDN back to analogue
• Through Somtech you arrange your ADSL service requirements and a set-up fee is charged to you to check line usage for ADSL & conversion. £50 payable
• You order an ADSL router and services from Eclipse through Somtech. £215 for router, £40 for configuration.
• Organize you domain transfer, web hosting or email if required. £4 a month to Eclipse
• Attach and set-up equipment on the local network so the PC’s & server can use the ADSL line. From £80
• Set-up monthly payment to Eclipse for ADSL services from £33 a month
• Pay BT the rental for the actual line (cost as found on your phone bill for one standard phone line)

Set-Up Charges

£50 set-up

£265 router

£80* LAN setup

Total £395

Monthly Charges

£23* ADSL services

£4 Web Hosting & Email

£ Your monthly line rental

Total £27 plus your monthly line rental

We hope this quick guide helps you understand what is involved with ADSL services. Queries or questions are welcome at info@somtech.co.uk or at Eclipse Networking Web Site

All information was correct at the time of publication and may be subject to change