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FTTP ONT - Optical Network Terminator

FTTP ONT - Optical Network Terminator

Why do I need a separate Optical Network Terminator (ONT)?FTTP Openreach Optical Network Terminator

This takes the signals and data from the fibre optic cable and converts them into a form which your router can use to deliver superfast broadband around your premises. Its technical name is Optical Network Termination unit (ONT). In turn, your router talks to devices like your computer IP Telephone.

Why does the Openreach ONT need to be fixed to a surface?

Your Openreach Optical Network Terminator (ONT) needs to remain fixed to the wall or skirting as the thin green fibre optic cable can be delicate. Please be careful when cleaning around it and make sure everyone knows not to tamper with it. You need to ensure the mains plug remains connected whenever people are likely to need access to broadband. Unplugging the mains will cut off broadband immediately but inserting the plug again will restore normal speeds within a few minutes.

What does the reset button on the back of the Optical Network Terminator (ONT) do?

The reset button enables you to power cycle the modem without disconnecting the power cable. However, we only want you to use it if you've contacted us and we've asked you to do it.

WARNING - pressing for 10 seconds or more will return the device to factory settings and may render your broadband service unusable.

What is the BBU port on the back of the Optical Network Terminator (ONT) for?

BBU stands for Battery Back-Up. This port is not active at the moment, so you should not plug anything into it. We may activate it in future.

What are the Tel 1 & 2 sockets and light on the Optical Network Terminator (ONT) for?

These are not active at the moment, so you should not plug anything into the sockets. We may activate them in future.


How do I troubleshoot my Optical Network Terminator (ONT)?

Your Optical Network Terminator (ONT) has a number of status lights. Its Power, DSL and LAN1 lights should all glow a steady green. If any light is flashing or switched off, select the option which describes its status:

  • Power light is off
  • PON and LOS lights both flashing
  • Relevant Port light is off
Power light is off (this is the right-hand status light)

The mains is unplugged or there is a problem with the power supply or your modem. To check:

  1. Check that the Modem's plug is in and switched on at the mains socket.
  2. Unplug from the mains and check that your modem’s power cable is correctly inserted into the power socket underneath the modem.
  3. Plug the modem’s power cable back into mains power. Switch on the modem.
  4. If the Power light is still off, you'll need to get in touch. Find our contact details by clicking the contact us link on this page.
  5. Please have your computer turned on if you call.
  6. PON and LOS lights both flashing (these are the two left-hand lights)

Your modem is connecting. Please wait for a while (up to five minutes). If the PON light does not turn solid green:

  1. Check if anything, such as network maintenance, is affecting internet performance by viewing our Status page.
  2. Check that the thin white fibre optic cable is fully inserted
  3. If the PON and LOS lights are still both flashing, disconnect the power cable, wait a few moments, reconnect the power cable and wait a few more minutes for the Power light to switch on.
  4. If you still have problems, you'll need to get in touch.