xDSL Access

What is it?

Digital Subscriber Line (DSL) is one of the most common broadband technologies. It uses the copper pairs already going to almost every premises in the country to provide access, without interfering with phone calls. Asymmetric Digital Subscriber Line (ADSL) is the most common 'flavour' of DSL and is the one widely deployed in Ireland.

Where is it available?

ADSL is available in a number of areas around the country. Eircom has enabled over 100 exchanges and EsatBT has enabled around 40 exchanges. Eircom has also committed to enabling more exchanges with an eventual target of 220 exchanges.

How does it work?

A standard phoneline appears on your premises as a pair of copper wires from the local exchange terminated in a wall jack. When a telephone is plugged into this jack, it becomes part of the Public Switched Telephone Network (PSTN). DSL technologies were developed to maximise the existing copper infrastructure by allowing a signal at a higher frequency than phone conversations to travel over the same pair of wires to the same wall jack at the premises. This higher frequency signal doesn't interfere with voice conversations.

At both ends of the copper wire pair, electronic devices are placed on the copper wires to superimpose the signal. Also, a physical splitter is installed to allow both connections to use the wire. The device at the customer end, usually referred to as a DSL modem, can be stand alone, in which case it connects to your PC or network using USB or ethernet or it can be a card that goes inside the PC. DSL technologies allow Telcos to use existing cable plant to provide high speed or even broadband transmissions between user premises and the nearest local exchange. This avoids the very costly augmentation of the copper cable plant with fibre optic cable, wireless or other technologies.

Asymmetric Digital Subscriber Line (ADSL) is the most popular form of the technology. It has been around for a long time in telecom terms and is a very mature technology. Asymmetric means its bidirectional speeds are different. Typically, the fastest upload speed is 512kbps while the fastest download speed is 2Mbps.

Why is it asymmetrical? Because this 'flavour' of DSL is primarily intended for people who want to use the internet, especially for browsing. Typically when browsing, most of the information is flowing from the network to the computer so to maximise the link, ADSL is used. Of course, not everyone who wants high speed or broadband internet access wants it for browsing. Some will be just as concerned about the upload speed. Video conferencing, peer to peer applications like file sharing and collaboration tools and voice over internet protocol (VoIP) are a few of uses where a symmetrical connection is preferable.

Rate Adaptive Digital Subscriber Line (RADSL) is another flavour of the product which was introduced by Eircom earlier this year. This is similar to ADSL except that it can travel 5.5kms over copper wire while sacrificing some speed. It has a maximum download speed of 512kbps and a guaranteed minimum of 256kbps depending on the quality and distance over copper.

What does it cost?

One time costs: There is a signup fee which includes installation of the equipment on the premises. Some providers require you to buy the equipment while others don't. Most will allow you to supply your own modem which is usually less expensive and allows you to choose the most suitable hardware for your situation. Ongoing costs: Several services are available. Compared to older technology options like ISDN and leased lines, they are relatively cheap although Ireland is among the most expensive in Europe for DSL access.

Advantages and Disadvantages:

  • 1. It is always on.
  • 2. It doesn't interfere with phone calls.
  • 3. It is relatively fast.
  • 4. Installation is easy and not disruptive.
  • 5. There are typically a broad range of services available and upgrading is easy.
  • 6. Some providers offer a self install option which saves money and speeds up connection time
  • 7. It is a mature technology making it reliable and inexpensive to implement.
  • Disadvantages:
  • 1. It is dependant on several factors relating to the copper wire it travels on, including its quality and the distance to the customer.
  • 2. Asymmetric only in Ireland to date.
  • 3. As it relies on infrastructure owned by the incumbent provider (Eircom in Ireland), it can be difficult for other providers to offer the service.
  • How do I get it?: The first step is to see if the exchange your phoneline is connected to has been enabled. If you are interested in the entry level service at approximately €60, please check here for all providers In order to figure out if your phoneline is capable of supporting the service. This map is also the one to use for all higher grade services from Eircom and Netsource. If the service is generally available in your area, please then use the 'check your line' option to see if your phoneline qualifies. If you have more than one line, insert all lines, as some may qualify and others may not.
    For the higher grade services offered by EsatBT, please check here.

    If the service you require is available in your area and your phoneline qualifies, you're done. Order it and enjoy the experience:) If the service isn't available in your area, you have the option to register interest in the map link for Eircom. EsatBT unfortunately doesn't have the option at present.
    If the service is available in your area but your line doesn't qualify, you are probably somewhat frustrated by now. If you have come this far, you really want to have the service.
    Unfortunately, we don't have any quick and easy solution to your plight. However, we have a few suggestions.
    1. If your provider allows it, see if a neighbour can get the service and set up a wireless network to share the service among two or more users. Some guidelines here 2. Consider satellite options.


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    Notice to Reader: The information provided is a summary of research and industry experience up to the time of writing and is not meant to purport to be a complete or all-inclusive collection of information on the topic. It is only meant to give the reader a basis of information to understand the topic. To the best of our knowledge, it was accurate at time of posting but may have changed, not contain all material available or since released and no longer be accurate or valid. Readers are cautioned not to make decisions based solely on this material and are urged to verify information and perform their own current research. Opinions expressed by the author(s) are their own and not necessarily those of the company.