Learn about optical network terminal status lights

You can use the status lights on your optical network terminal (ONT) to help find and fix internet issues. An ONT may also be called a Service box.

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ONT connections
If you’re having issues and can’t get your ONT to power up, contact us.

Status light	State	Description and action needed
POWER	Green (solid)	The ONT is on.
	Off	The ONT is off. You should: Make sure the network power cable is plugged into a working outlet. Press the power button to make sure the power is on.
	Red	There’s a problem with the ONT.
PON	Green (solid)	The ONT is connected to the AT&T network.
	Green (flashing)	The ONT is connecting to the AT&T network.
	Off	You should: Make sure the power LED is solid green. Check the fiber cable to be sure it’s connected to the PON port. If both of these look good, check for local internet outages.
ALARM	Off	The ONT is working properly.
ALARM	Red (solid)	The ONT isn’t working as expected. Make sure the fiber cable is connected to the PON port.
DATA	Off	The Ethernet isn’t working. You should: Make sure the power LED is solid green. Check both ends of the red ONT cable provided in your box. It should be connected to the Ethernet port of the ONT and the red ONT port on the back of your gateway. Make sure the ONT port LED on the back of your gateway is green.
	Green (Solid)	The ONT is connected to your gateway at 10 or 100Mbps.
	Green (flashing)	The ONT has data activity at 10 or 100Mbps.
	Yellow (Solid)	The ONT is connected to your gateway at 1000Mbps. (Service speed may vary)
	Yellow (Flashing)	The ONT has data activity at 1000Mbps. (Service speed may vary)

Indoor 020 ONT
If you’re having issues and can’t get your ONT to power up, contact us.

Status light	State	Description and action needed
PWR	Green (solid)	The ONT is on.
PWR	Off	The ONT is off. You should: Make sure the network power cable is plugged into a working outlet. Press the power button to make sure the power is on.
BTRY	Off	This isn’t used for your AT&T internet service.
FAIL	Off	The ONT is working as expected.
	Green (solid)	There’s a problem with the ONT.
	Green (flashing)	The ONT is connecting to the AT&T network.
LAN 1G	Green (solid)	The ONT is connected to your gateway.
	Green (flashing)	The ONT has data activity.
	Off	The Ethernet isn’t working. You should: Make sure the power LED is solid green. Check both ends of the red ONT cable. It should be connected to the Ethernet port of the ONT and the ONT port on the back of your gateway. Make sure the ONT port LED on the back of your gateway is green.
LAN 10G	Off	This isn’t used for your AT&T internet service.
NTWK	Green (solid)	The ONT is connected to the AT&T network.
NTWK	Off	The ONT isn’t working as expected.
MGMT	Green (solid)	The ONT is connected.
	Green (flashing)	The ONT is downloading software.
	Off	The ONT isn’t connected to the AT&T network.

Outdoor ONT
Check to make sure the power supply LED is On and Green. If it isn’t, make sure it’s plugged in to a working outlet.

If it’s plugged in and still not working, contact us.

Last updated: February 14, 2024