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Broadband Faults Guide - FTTC

Broadband Faults Guide - FTTC

Broadband Faults Guide - FTTC

FTTC Faults Guide

Fibre to the Cabinet is a relatively new technology in terms of fault reporting and the tools we have at our disposal are quite limited for this reason at the moment – this is likely to change in the future. This guide has been written to offer you the support you may require when you’re having problems with your fibre connection.

Do I have a fault?

That really depends on the problem that you are experiencing. If you’re having problems staying connected to the internet or can’t even connect at all, it’s likely you’ve got a fault. The big area surrounding fibre is speed faults and it can be quite difficult to find a common ground on what we find acceptable in terms of speed and what you find acceptable, based on your sign up speed estimates. Let’s first of all take a look at the different fault types that you may experience.

Frequent Disconnection (DCN)

This fault is where your connection is having trouble staying connected to the internet. We can offer support on this type of fault by showing you a Visual RADIUS:
 If we can see the connection is dropping, it’s something we’re definitely interested in looking at for you. The disconnections could be caused by your own equipment, so it’s important that you ensure there is nothing within your premises that might be causing this problem, such as a microfilter being connected to your main telephone socket.
Your connection should be set up as per the below diagram:

If your equipment is connected up correctly and you’re still having problems staying connected, it’s a good idea to rule out the router as a potential cause of the problem. You can connect directly to the Openreach Modem as shown here for Windows 7 and here for Windows XP.
If the connection still drops connected in this way (PPPoE), you should raise a fault with us at so we can investigate this further.

No Sync (NSC)

A No Sync fault can be very frustrating, given that this will mean you have no connection at all. You can tell if this is the case by looking at your Openreach Modem and you may notice that your DSL light is either not on or is flashing. If the DSL light is flashing you should:

  • Check the DSL socket and make sure the cable is firmly connected. The other end of the cable should be firmly connected into the telephone line face plate.


  • Your modem could have over-heated. Make sure it's in well ventilated, free-air and:1. Power off for 10 minutes.2. Power back on and wait a few minutes for the lights to come back on.


  • Try resetting the modem:1. Press and hold down the Resetbutton on the back of the modem for 5 seconds.2. Release the button and wait a few minutes for the Power light to come on.


  • Try disconnecting the power cable - wait a few minutes & then reconnect. After a few more minutes the Power light should come on.

 If you are still experiencing problems, you’d be best reporting this fault to us at so that our Faults Team can investigate further.

Authentication Fault (Auth)

Most of the work required on authentication via Fibre to the Cabinet is dealt with using automated testing on the Wholesale network and with Openreach and their own Diagnostics Centre of Excellence (DCoE). We raise your fault to our supplier and once they complete diagnostics on the line, your service will either be working again, or require an engineer visit.
In some instances you may find an error message “concentrator not reachable”. In most cases this fault can be cleared within a few minutes by powering off your router, waiting 10 minutes, powering back on and forcing the connection to reconnect within the router configuration.
Further information on this fault type, can be found here.

Speed Fault (EPP)

Speed faults probably account for 85%+ of the faults that we receive. This is because the speeds that you receive are lower than the estimate we provided or you believe that your line can be improved by reporting a fault to us.
When you sign up with us, we provide you with an estimate based on the length of the copper cabling between your PCP (Cabinet) and DP (Distribution Point). Bear in mind that line quality may not be included in your estimate, for example, if your line has aluminum in it, this will not be factored into your speed estimate as it is done on line length.
It’s important to understand that the estimate IS only an estimate and isn’t a guaranteed speed. Having said that, we’re extremely active in looking at problems which you report to us and we appreciate that we should be doing our best to get you speeds that your line can support. If you believe you have a fault, please read the below checks that you should complete before reporting this to us:

  • Ensure you are connected to your router with an Ethernet Cable when running a Speed Test. Your throughput speeds are not guaranteed via a Wireless Connection
  • Close any/all background applications when running speed tests to ensure your bandwidth isn’t being over utilised by other applications
  • Try a PPPoE connection (bypassing the router) as shown here and here
  • Run the BT Speedtester including ‘Further Diagnostics’

 If you haven’t done all of the above checks before reporting a Speed Fault to us, this will likely delay the progress as we will request that these checks are completed before we raise this to our suppliers.

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If you have a modem that is capable of delivering linestats such as SNR and gain you might learn a lot about the quality of your connection.