Cable Access

Where is it available?

It is not widely available as the cost to upgrade the network is high. Some areas of Dublin and a few rural areas are enabled through different providers.

How does it work?

Cable TV has been around for many years. The infrastructure consists of a 'Head End', where the equipment which receives the signals resides and a coaxial cable or hybrid fibre coaxial (HFC) distribution network. This distribution network was designed to be a one way system where the signal was pushed from the head end to the users' television.

More recently, Cable operators realised that this infrastructure could be maximised by making it two way, in which case internet access and phone service could now be delivered also. Cable internet access in other countries has been the single biggest reason for the Telcos to roll out DSL services as it is very effective competition and is often priced cheaper that comparable Telco offerings.

Ireland invested in Cable TV networks as an early adopter and as such, the networks are typically very old now in technology terms. We are now paying for this as to upgrade the networks and make them two way will be a very costly and disruptive proposition. This (along with the crash in telecommunications) is the reason why there are so few areas of Ireland where Cable access is available.

In network terms, it differs somewhat from its nearest competitor, DSL. The wiring runs from home to home in a daisy chain fashion (referred to as a bus topology) so it is shared. Wiring from a Telco exchange is dedicated to each house (referred to as a star topology) and so, isn't shared. The bandwidth is shared between all users on the particular line so the speed of the connection will vary. Security can also be a bigger issue that with DSL as many are sharing the same wire. However, a firewall should always be used when always on connections are adopted.

What does it cost?

One time costs:

Current CATV subscribers pay a nominal fee to have the service installed. This cost will include the hardware necessary for the service.

Ongoing costs:

The costs vary but are generally in the range of €35 per month for a 1024/128kbps connection. See table for various offerings.

Advantages and Disadvantages:


1. It is always on.
2. Far faster than dialup.
3. It makes use of existing infrastructure although it has to be upgraded in most cases.
4. Relatively inexpensive and typically less expensive than DSL offerings.
5. The install is quite straightforward and there is a minimum of disruption.
6. It is widely adopted worldwide which makes the equipment inexpensive to buy.
7. It provides the stimulus for Telco's to offer DSL as it is a threat to dialup revenues.


1. The bandwidth is shared among many so it can vary quite considerably.
2. At present, it is asymmetric only. This is a technology limitation.
3. Only the incumbent provider (the one who owns the infrastructure) is automatically able to supply the service. Unbundling of the infrastructure is more difficult technically.
4. Security is an issue currently as people on the same line can quite easily 'hack' others computers. A properly implemented firewall will alleviate this risk.


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