What are ADSL and cable modems and how do they work?

As broadband hardware improved and modems began to become more sophisticated, so the internet began to expand into an increasing number of households. Indeed fast modems are now used by internet users every day – most notably in the form of ADSL and cable modems.

What are ADSL and cable modems and how do they work?

The next stage in the evolution of modems was ADSL and cable. Here is a brief overview of each type:

  • ADSL modems – Standing for asymmetric digital subscriber line (ADSL), these modems send data faster in one direction than they do in another. They work using the copper wire that runs from a home/office to the nearest telephone exchange. This wire is capable of holding far more data than is used for your telephone’s voice channel and so if you are equipped with an ADSL modem you can pick up digital high speed transmissions.

    The capacity of an ADSL modem is around 8Mb from the telephone exchange to your home and around 1Mb from your home to the telephone exchange. This is why you will receive far higher download speeds than upload speeds. Alongside an ADSL modem you will need micro-filters to prevent crackling on your phone line – these should be supplied by your ISP.

  • Cable modems – Much like ADSL takes advantage of unused bandwidth on a telephone line, cable modems grab on to the unused bandwidth in the cable television infrastructure. Generally speaking, they are most popular in the USA, but have become increasingly popular in the UK in recent years.

    With a cable modem you have the advantage of a potentially larger service range, which usually starts at 2Mb and can range as high as 50Mb for some business broadband packages. The upstream rate is also higher and usually starts at 384kb and peaks at around 20Mb.

So which is better, a cable modem or ADSL?

Both systems have their strengths and weaknesses. Certainly, cable modems have the advantage of larger bandwidth and therefore you are more likely to receive faster speeds. However, many cable internet service providers will only tie in broadband access as part of a television deal. This has led to the introduction of bundled broadband products, where broadband packages are tied to phone and television services. Thankfully due to a competitive market, prices have remained cheap.

For both cable and ADSL modems, service speeds can depend on how many people are using the service at the same time. In theory, the operator should monitor the system to ensure customers always receive adequate bandwidth.

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