Slow ADSL: 9 tips to improve your speed

By The SpeedFibre team, updated . 3 min read.

Slow ADSL: 9 tips to improve your speed
In short ADSL is limited by the length of your copper line: no trick beats that limit. But poor home wiring (filter, extension, secondary socket, interference) can cost you a lot. Connect the modem to the main socket with a good filter and a short cable.
Contents
  1. Understanding ADSL's limit
  2. 9 checks that gain speed
  3. What results to expect
  4. The alternative: fibre or a 4G/5G router

Two factors set your ADSL speed: the line between your home and the provider's equipment, which you do not control, and your home installation, which is often responsible for a big loss and which you can fix.

Understanding ADSL's limit

The ADSL signal weakens with distance. The further away you are, the lower the speed your modem syncs at. The sync rate, shown in the modem interface, is the maximum your line can reach; the speed measured by a test is slightly lower.

9 checks that gain speed

  1. Plug the modem into the main socket: the first socket in the home, where the line comes in. Secondary sockets add cable length and interference.
  2. Remove phone extensions: use a short cable between socket and modem.
  3. Fit an ADSL filter on every socket with a landline phone, and replace any old or damaged filter.
  4. Unplug unused equipment on the line: old fax machines, splitters, cables that no longer serve.
  5. Keep the cable away from interference: power supplies, dimmers, fridges, overloaded power strips.
  6. Restart the modem to force a new sync.
  7. Test over an Ethernet cable: even if ADSL is slow, this rules out Wi-Fi.
  8. Check the interface: sync rate and noise margin. Frequent disconnections can indicate an unstable line.
  9. Report a faulty line: crackling on the phone, drop-outs in wet weather, a sync rate that keeps falling. These point to a physical problem.

Measure your connection now. Start the test

What results to expect

Line situationCommon ADSL2+ speed
Very close to the exchange15 to 20 Mbps
Medium distance6 to 12 Mbps
Long line1 to 5 Mbps

If you are already close to your line's maximum, no tweak will bring a significant gain.

The alternative: fibre or a 4G/5G router

ADSL is fine for one person with light use. If several people share it, you work from home or children follow online classes, check whether fibre is available. Compare in fibre or ADSL and 4G/5G router or fibre.

#WiFiDiagnosis#Ping#Troubleshooting

Sources and further reading

Frequently asked questions

Is an ADSL filter required?

Yes, on every socket with a landline phone on the same line, otherwise the phone disturbs the ADSL signal.

Why does my ADSL drop when it rains?

Moisture in a cable or a box in poor condition disturbs the copper line. Report it to your provider.

Will a new modem increase speed?

Only if the old one is faulty. Maximum speed remains limited by the line.

The SpeedFibre team Guides written and reviewed by a telecom engineer specialised in fibre optics (FTTH), with more than 8 years of hands-on network maintenance and measurement. Editorial policy.

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