4 If you've having problems with your broadband or phone connection, it's important to try an isolation test. Devices that you have plugged into your phone lines can interfere with your broadband service, and an isolation test checks whether things such as the internal wiring of your house, a faulty ADSL filter, or another device is causing your problems.
- Disconnect all private equipment plugged into a jackpoint e.g. double adapters, phones, filters, extension cords, fax machines, modems, Sky etc.
- Wait for at least 30 seconds to allow the line to reset.
- Plug the modem back in, without a filter, and wait for it to reconnect - if the lights labelled 'ADSL Sync' (sometimes labelled 'ADSL', 'Sync', 'WAN' or 'Broadband') and 'Internet'(sometimes labelled 'Online') light up, then your modem has reconnected.
- If your modem reconnects: then this means that your other devices or equipment are causing interference on your phone line. Plug your equipment back in piece by piece, checking the connection each time. When the problem returns then you have discovered the faulty equipment. Keep testing the rest of your equipmment as well.
- If your modem doesn't reconnect: then the problem may lie with your jackpoint or phone cable. Try a different cable, and if that doesn't work, then try the other jackpoints in your house, still checking the connection each time.
4 If you discover a piece of faulty equipment, it will either need to be replaced, or may simply require a new ADSL filter.
When Do I need to perform isolation test?
4 You should do isolation test if you are on ADSL connection and having below problems.
- No ADSL light on modem (No Sync)
- Intermittent connection
- Slow speed (low sync rate)
- Buzzing sound on telephone line