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What do the lights on the Openreach modem mean?

If you are fibre customer you might have an Openreach modem (or ONT) installed. This white box connects to a fibre optic cable, which runs directly to your house and allows you to access our fibre network for broadband and voice.

There are several lights on the ONT, when these lights change colour or flash, it means something is happening.

Customers will have one of five different types of Openreach modem, they all work in the same way, but the type and number of lights may vary between devices. 

The table at the bottom explains what the lights mean.

Huawei 1-port modem

Lights: Power, Tel, Port, LOS and PON.

Huawei 4-port modem

Lights: Power, Tel (x2), Port (x4), LOS and PON.

Huawei 4-port Openreach modem

ECI modem

Lights: Power, Optical, Tel (x2) and LAN (x4)

ECI fibre modem

ECI C-Series modem

Lights: Power, Optical, Tel (x2) and LAN (x4)

ECI C-series modem

Nokia modem

Lights: Power, PON, TEL (x2) and Port

Nokia modem

Learn about what the lights on the Openreach fibre modem mean and what to do if they show that there's a problem.

 

Light

Status

Meaning

What to do

POWER (right-hand light)

Green

Openreach fibre modem is on.

Check PON and LOS status below.

Off

Openreach fibre modem is off.

Check the mains plug is in.

PON and LOS (left-hand lights)

PON solid green

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

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

PON flashing and LOS off

Openreach fibre modem is communicating with BT 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 BT exchange.

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

PORT1-PORT4

On (any)

Ethernet connection is normal between Openreach fibre modem and Hub (Port 1 is where engineer will install).

There may be a connection problem - check your Hub.

Blinking (any)

Data is being transmitted through the port.

There may be a connection problem - check your Hub.

Off (all)

Ethernet cable to Hub is not inserted or broken.

Check physical connection at both ends of the cable. Try new cable if needed.

TEL 1-2

On (any)

The fibre home phone line is live on your modem.

Initially, you need to activate your fibre home phone line.

Blinking (any)

Fibre home phone line is not activated.

Wait until light turns solid green.

Off (all)

Fibre home phone line is not activated.

Check the mains cable is plugged in and the modem is switched on.

Optical

Green solid

Connected

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

 

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