How to do an Isolation Test on fixed line connection for broadband or phone

This article explains how an Isolation Test can help identify possible causes related to a phone or broadband issue. Performing this test may avoid a technician call out charge where a fault is caused by your hardware or device.

We recommend performing the isolation test prior to your call to our contact centre, as this may significantly reduce your call time.

Issues you may be experiencing:

  • Noisy phone line (echo, cutting out, static or interference)
  • Loss of broadband connection (unable to browse or time out errors)
  • Slow broadband, slow browsing speeds.

There are 4 things to check for an isolation test, they are:

  1. Jack point (phone jack or broadband jack point could be faulty inside the premises)
  2. Device (phone, fax machines, modem etc...)
  3. Cables (extension cables, 2-way or multi plugs, broadband line filters)
  4. Lines (lines could be faulty outside of the premises such as exchange, road or pillars).

Steps to perform an isolation test

Unplug everything that is connected to a jack point.

This includes:

  • Phones, (cordless and corded), modems, fax machines and answering machines
  • Filters, extension cables and adapters
  • SKY TV (if it is connected to a jack point)

Connect a device that has been confirmed as working into the jack point

E.g. such as phone or broadband modem that works elsewhere).

  • Check the device to confirm the service is working on the connected jack point.
  • Repeat the steps until all jack points have been tested.
  • When a dial tone (phone device), ADSL indicator or Sync light (this will vary depending on the type of modem used) is present, it means the jack point is okay and the issue may be caused by the device or cables.
  • Plug the device directly into a known working jack point
  • Disconnect any extension leads or adapters
  • Test the device and check if it can obtain service

Check the cables

  • Unplug the phone cable that is connected behind the device and replace it with a similar cable, where possible.
  • Plug your device directly into a jack point (without additional extensions or adapters).
  • Confirm the services are working:
    - Phone - You will hear a dial tone.
    - Broadband - ADSL indicator will be on this will vary depending on the type of modem.  If there was an adapter used (e.g. double adapter, ADSL filter), add it back to the test and check if the service is still working.

Don't forget to reconnect devices that have been identified without any issues.

What should I do now?

Depending on the outcome of your isolation test, you may need to call us for further assistance.

For home phone lines: If you can't get a dial tone on any of your sockets, it's possible your telephone line is dead due to other causes. If you have a mobile phone, call your own number and make a note of whether it rings out or is engaged, or whatever message you might hear, then please contact us.

For broadband: If your connection doesn't come back during these tests, and your modem is definitely in good working order, it's possible your broadband service has developed a fault which requires a tech to investigate. Please contact us to lodge a fault.

Let our contact centre support agent know what steps you have taken already. It will save them guiding you through the process again.

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