What the Openreach modem lights mean

Types of modem

If you're a 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.

You'll have 1 of the 5 different types of Openreach modem, they all work in the same way, but the type and number of lights varies between device.

Huawei 1-port modem

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

Huawei 4-port modem

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

ECI modem

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

ECI C-Series modem

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

Nokia modem

Lights: Power, PON, LOS and Port

Modem lights

Power (right-hand light)

No light

If there is no light, the Openreach fibre modem is off.

What to do

Check the mains plug is in.
Green

If the light is green the Openreach fibre modem is on.

What to do

Check the PON and LOS status below.

PON and LOS (left-hand lights)

PON solid green

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

What to do

Check physical connection at both ends of the cable between the Openreach fibre modem and hub. Try a new cable if needed.
PON flashing and LOS off

Openreach fibre modem is communicating with BT exchange for verification.

What to do

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.

What to do

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 5 minutes for the Openreach fibre modem to attempt to reconnect.

PORT1-PORT4

All lights on

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

What to do

There may be a connection problem - check your hub.
Any lights blinking

Data is being transmitted through the port.

What to do

There may be a connection problem - check your hub.
All lights off

Ethernet cable to hub is not inserted or broken.

What to do

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

TEL 1-2

All lights on

The fibre home phone line is live on your modem.

What to do

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

Fibre home phone line is not activated.

What to do

Wait until light turns solid green.
All lights off

Fibre home phone line is not activated.

What to do

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

Optical

Solid green

Connected.

What to do

Check cable connection at both ends, between the Openreach modem and hub. Try a new cable if needed.

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What the Openreach modem lights mean

In this article

Types of modem

Types of modem

Modem lights

Modem lights

What to do

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