Intermittent Connection Faults

If you're having intermittent connection faults with your broadband read our guide for handy hints on troubleshooting.

1. About intermittment connection faults
2. Dealing with intermittent connection faults
3. Line statistics explained

• Upstream and downstream
• Channel mode
• Line (Downstream) Attenuation
• SNR (Signal to Noise Ratio)
• SNR Margin (or Noise Margin)

4. MaxDSL (Up-to 8Mb broadband)
   

1. About intermittent connection faults
If your broadband connection comes and goes, seemingly at random intervals, you have an intermittent connection fault. These are not to be confused with speed faults, where you might experience a drop in your connection speed.
[TOP]

2. Dealing with intermittent connection faults
Running through the Broadband Fault Checker will help you find the cause of your fault, or at least report the fault to our support team for further investigation. The Broadband Fault Checker will ask you to complete some checks. This article provides help with completing these.

Check your microfilters
The most common cause of intermittent connection faults is a problem with microfilters. See our Guide To Fitting Microfilters for more information.

Check your cables and remove extensions
Faulty cables are another common cause of connection problems. You really need to test your connection using only your master socket.

Check your modem/router
Sometimes a glitch in your modem or router can cause your connection to drop. Check to see if your connection comes back after restarting your hardware. If it always comes back after restarting, try re-installing your hardware. Modems will need their drivers removed, then re-installed. Routers should be reset to their factory settings. Your hardware's user manual should show you how to do this. If you bought your hardware from us read our Modem And Router Setup Guides for help.

Check your telephone line
Check for a dial tone on your phone. Telephone line faults are often overlooked when broadband is running on its own line with no telephone attached. If you don't hear a dial tone you need to report the problem as a telephone fault to BT by ringing 151. If your telephone service is provided by PlusNet then you should report the fault online using the Help Assistant.

Check for background noise on your telephone line
If you can hear crackling, pops or whistles, this may mean:

• A device on your line is causing interference (not properly filtered, or maybe incompatible with broadband service)
• A faulty microfilter
• A telephone line fault (again, report this directly to BT)

Check for possible interference
Broadband (especially the high-speed MaxDSL service) can be affected by different types of electrical or radio interference.

Devices that can interfere with broadband connections include:

Broadband equipment (e.g. wireless hardware or a spare modem left connected on an extension)
Computer equipment (e.g. scanners, external drives etc)
Electrical appliances (e.g. microwave ovens, halogen lamps and Christmas tree lights)
RF equipment (e.g. remote control garage doors, AM radios and central heating thermostats)

If you notice a pattern to the times you are getting disconnected, keep an eye on what other electrical equipment might be in use at the same time.

If you get intermittently disconnected but the sync light on your broadband hardware is solid green, you are advised to check for idle settings on your hardware that might be automatically disconnecting you.

Check signal quality
After making all the above checks, it's possible that the connection problem may be the result of a fault on the telephone line, or network.

Try keeping a log of when your disconnections occur. If you can spot a pattern, it will help us to monitor the problem as it occurs.

Check to see if your modem or router provides connection statistics. Reporting these can help identify if your connection problems are the result of a poor quality connection.

Note: Heavy rain and other extreme weather conditions may cause connection problems, as well as affecting the speed of your broadband connection. You should bear this in mind before reporting a broadband fault.
[TOP]

3. Line statistics explained

Connection statistics can seem a bit overwhelming to an inexperienced user. However, here's a brief and simple guide to help you understand what some of them mean.

Upstream and downstream
Your broadband connection can send data in two directions. Data sent from your modem out to the Internet is said to be upstream. Most data travels from the Internet to your modem, this is downstream.

Channel mode
Either Fast or Interleaved. Interleaved mode can increase the reliability of your connection. You can learn more about the benefits of Interleaving in our Advanced Guide to Broadband Max.

Line (Downstream) Attenuation
This describes the loss of your broadband signal over distance. The greater your distance from your local telephone exchange, the weaker your received signal is likely to be. If the quality of the telephone cable is poor, this can also increase attenuation.

• 75 dB+ Out of range for broadband
• 60-75 dB up to 512kbps
• 43-60dB up to 1Mbps (higher speeds with MaxDSL)
• 0-42dB up to 2Mbps+ (higher speeds with MaxDSL)
  

A dB (Decibel) is a measure of sound intensity. It's a logarithmic unit, so an increase in 3dB is equal to double your original intensity.

SNR (Signal to Noise Ratio)
This is a bit like television reception. A high SNR means you're getting a good clean signal with no static or interference. A low SNR and broadband signal is being drowned out by noise. Watching a bad TV picture may be annoying, but you can still use your TV. With your broadband, lots of noise can quickly lead to a complete loss of your connection. SNR is not usually provided as a line stat, most hardware will show SNR Margin instead.

SNR Margin (or Noise Margin)
This is a measure of the difference between your current SNR and the SNR that is required to keep a reliable service at your connection speed. If your SNR is very close to the minimum required SNR, you are more likely to suffer intermittent connection faults, or slowdowns. You need a high margin to ensure that bursts of interference don't cause constant disconnections.

With traditional broadband, the higher the SNR Margin, the better. With MaxDSL the faster speeds are only available as a trade-off with what your line can reliably support. The Target SNR Margin is about 6dB. If your broadband is provided through an LLU (Local Loop Unbundled) network, this target SNR Margin may be as high as 12dB.
[TOP]

4. MaxDSL (Up-to 8Mb broadband)

The MaxDSL technology that offers increased connection speeds up to 8Mbps is more sensitive to line quality problems than regular broadband.

MaxDSL tries to adapt to your line to provide the best balance between connection speed and service reliability. The target SNR Margin is 6dB, which can support the fastest connection speeds. If your line is subject to interference your SNR Margin will be increased, which will reduce your connection speed.

You can learn more by reading our Advanced Guide to Broadband Max
[TOP]

Rate this page

Has this page helped you solve your problem? Your feedback helps us to improve the help we provide.