ADSL Isolation Test

What is an Isolation Test?

If you are having issues with your ADSL/ADSL2+ internet connection we will ask you to perform an isolation test. Through process of elimination, this test will help single out an issue with a piece of hardware within your premises.

 Isolation Test Steps

  1. Remove all hardware/equipment that shares the phone line your internet is on. ie- modems, phone handsets, ADSL splitters & filters, PABX phone systems, fax machines, alarm systems, Pay TV boxes and EFTPOS & HICAPS terminals.
  2. Plug only the modem back into the phone line using just a single, short cable and without a filter.
  3. Plug a laptop or computer into the modem using a network/patch cable & test the internet and see if your problem is fixed. If yes, go to step 6.
  4. Connect the modem on any another sockets or points that the phone line is connected to and test again.
  5. Repeat the above steps using another modem if your internet problems continue.
  6. If this resolves your problem add hardware/equipment back on the phone line one at a time and test after each item is added to rule out other issues.


  • Faulty phone cables, modems and splitters/filters are the most common causes of internet problems.
  • Use the shortest phone cables as possible, never use extension phone cables with an ADSL service.
  • Keep a spare ADSL modem, spare ADSL splitter/filter & spare phone cables handy in case one of these devices fail.
  • Use a central ADSL filter where possible as it will help ADSL to perform better when using other services/hardware on the same line. A phone technician is required to install a central filter correctly.

For further troubleshooting please call our Tech Team on 1800 FLUFFY (1800 358 339)