Basic FTTC Troubleshooting Guide

This is a basic FTTC troubleshooting guide. Before proceeding, you should try to eliminate any potential problems with your own network. Please see our Basic Connectivity Troubleshooting guide for more information on this.

What is FTTC?

FTTC stands for Fibre To The Cabinet. FTTC utilises the existing broadband infrastructure to deliver next generation connectivity, as opposed to Fibre To The Premises, which has the entire connection as fibre optic lines to the premises. Below is a diagram from the House Of Lords Committee Inquiry On Communications that sums up in a nutshell where FTTC sits in comparison to other forms of connectivity:

 FTTC Network Architecture Diagram


With FTTC, a fibre optic connection runs all the way from the core network through to the local exchange after which it runs to a street cabinet. From here, several connections split off from one cabinet into multiple homes, hence fibre ‘To The Cabinet’. The last leg of the connection is referred to as the ‘Last Mile.’ Though not always strictly a mile long, this length of copper wire is the last connection from the cabinet to your house and, like traditional ADSL broadband, the distance between the cabinet and the premises will determine your ultimate speed. The greater the distance, the slower your download and upload speeds will be. Typically, upload speeds will be a lot less than the download, but you should still be able to achieve much better upload performance than ADSL. Dependent on distances, FTTC speeds can vary quite dramatically, with download speeds of 5mb all the way up to 80mb.

My FTTC connection is down

When your FTTC connection is hard down, troubleshooting and fixing the problem is very similar to that of an EFM or Ethernet Leased Line connection – your Internet router will connect into an NTE box provided by your ISP, and this will sit between the router and the wall socket. It is important to familiarise yourself with this box while the connection is in a working state. Different ISP’s provide different brands of NTE, so when the box is first installed, try to get some documentation to go with it from your ISP and make sure you are aware of what the lights on there indicate. This means that when the connection fails, you will be able to determine what light statuses have changed, and this information is invaluable to the support desk at your provider.

Always try rebooting the kit first. This includes the router and the NTE that might sit between the router and the wall socket. Check all connections are seated and connected properly – the wire from the wall into the NTE device, and the wire that connects this device to your router.

For reference, the older style FTTC connections will have your kit connecting into something similar to these i.e. a BT modem:

With the connection being RJ45 into one of the LAN ports and the DSL port connecting to the wall socket.

And a new style FTTC will connect with RJ11 directly to the wall socket into one of these:

If you have rebooted all of the kit, made sure that everything is connected as it should be and eliminated it being a problem with your own network (please see our Basic Connectivity Troubleshooting guide), then you have little choice but to speak to your FTTC provider and log a fault with their support desk. Going to them with as much information as possible is always handy, so make sure you tell them that you have checked all of the connections and rebooted / reseated everything where applicable. As mentioned above, being familiar with the lights on both your router and your NTE come in very handy at this point — you can identify the status of the connection from the NTE to the exchange, from the NTE to the router, and the status of the connection itself, all by keeping track of the lights on the front and back of your bits of kits. Convey this information to your support desk. These lights may seem insignificant when everything is working, but knowing what is different when something goes wrong can speed up the process dramatically, especially those on the NTE box.

My FTTC connection is running slowly or intemittently

Troubleshooting a slow or intermittent connection for FTTC is very limited. The NTE box that sits as the point of communication between your router and the exchange is key, and nearly all the time your provider (or BT if applicable) will have this NTE box locked down so you cannot access it directly. You will see that you can connect a laptop or device directly to the NTE via Ethernet cable, but gaining access to it will require access details from your provider. Some providers prefer the end user not to do this, and will handle everything remotely, where as others will be happy to talk you through this step and run some tests from the NTE yourself. In either instance, you will need to speak to your provider about this step.

Before doing so, it is a good idea to check our other guides to try and determine if the slowness or intermittency is occurring somewhere else along the chain. Please see our Basic Connectivity Troubleshooting and Basic Router Troubleshooting guides for more information and help. If you have run through all these checks and eliminated various things, always go to your provider with this information. This information will prove very useful along the troubleshooting process.