We often get customers asking about quotes for Central Filter installations, as a result of their ISP telling them it will solve all their problems. Depending on who you get to do the work, it can cost up to $300 which for most can be quite an investment. Before jumping in and getting a Central Filter (also known as a CF) installed, its best to check whether or not you really need one.
If you are experiencing slow ADSL speeds or perhaps have a buzzing noise on your line, one of the first things Tech Support will ask you is "do you have an Alarm system?". If so, they may recommend or upsell you a Central Filter to correct the problem, which can be misleading. It's not a one-size-fits-all solution.
Noise on the line (regardless of what frequency) may indeed be removed by filtering, but if the problem is caused by corrosion or an earth fault on your line, your internet will still be slow and may even drop out. In this case, using a filter is a quick fix that doesn't actually address the underlying problem. Therefore we recommend you call a technician to come and test your internal cabling (phone cables, sockets, terminations, and your equipment including phones, fax, EFTPOS units) as they may be able to fix your problem for much cheaper than the cost of a CF.
If you have a Back to Base alarm system or an auto dailer (such as MediCall or other Panic Button) that uses your landline phone service, it will interfere with your ADSL internet, and vice versa (unless of course you have a GSM auto dialler, which has a mobile phone SIM card inside, and doesn't use the phone line). A Central Filter in this case is essential; as always, we recommend you call around for quotes to get the best deal, and make sure the technician is licenced before starting any work in your premises.
Note: Having a CF installed can indeed be of benefit to any household, but is not always a necessity. However, should your R.E.N. exceed 3.0 or if you have more than 3 devices plugged in to your telephone line (excluding the modem), ISPs will require a CF to be installed to ensure maximum performance.