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:
Advantages and Disadvantages:Advantages:
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.
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