If you’re an FTTP customer, it’s likely you’ll have an Openreach modem (otherwise known as an ONT) installed. This white box connects to a fibre-optic cable that runs to your house and enables you to access our FTTP fibre network for broadband.

The picture below here demonstrates what an ONT looks like. This needs to be switched on at all times.


The router is connected to the ONT through the ethernet cable - one end of the ethernet in the ONT and the other into the red port on the back of our router.

Lights and Troubleshooting




What to do

POWER (Left-hand light)


Fibre modem is on.

Check PON and LOS status below.


Fibre modem is off.

Check the mains plug is in.

PON and LOS (right-hand lights)

PON solid green

Fibre optic link to exchange is working and recognises your fibre modem.

Check physical connection at both ends of the cable between the fibre modem and Hub. Try new cable if needed.

PON flashing and LOS off

Fibre modem is communicating with exchange for verification.

Wait until light turns solid green.

PON off, or PON and LOS both flashing

Fibre optic link is not connected or there's a problem between your property and the exchange.

Check that the thin white fibre optic cable coming into your fibre modem is inserted and not damaged. Turn the fibre modem's power off, then back on and wait five minutes for the fibre modem to attempt to reconnect.