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Every AT&T modem and router comes with a set of LED lights like Power, Ethernet, DSL, Internet, etc. Usually, each symbol stays solid green when working properly. However, if something is wrong, like the AT&T internet is slow, status lights on the modem or router might blink or turn off.

Based on a particular icon's light color and state, you can identify its problem, cause, and fix it. Thus it is crucial to first understand all AT&T status lights, their significance, ideal states, problematic states, possible causes & solutions.

ATT Modem Lights

Light NameStateMeaning
PowerSolid GreenModem is powered normally and operational
Light OffThe modem is off, or malfunctioning
Flashing RedPower on/self-test in progress
Solid RedPower on/self-test failed, or modem has
malfunctioned
EthernetSolid GreenActive Ethernet Connection between a
device and modem
Flashing GreenTraffic between the connected device and
modem
Flashing Green Simultaneously
with DSL Status Light
Hardware failure detected. Contact
Technical Support
Light OffThe modem is off or there is no ethernet
connectivity
DSLSolid GreenModem is connected to the DSL
Flashing GreenModem is trying to sync to the DSL
Flashing Red/GreenModem failed to sync three times
Flashing Red Simultaneously
with Ethernet Status Light
Problem in the hardware. You need to contact the
technician
Solid RedHardware failure detected. Contact the
technician
InternetLight OffModem is off, or it is not connected to the
internet.
Flashing GreenModem is trying to connect to the internet
Solid GreenModem is successfully connected to the
internet
Activity
Status
Flashing GreenInbound internet traffic
Light OffModem is off or no inbound traffic

AT&T Modem Lights: Meanings, States, Fixes

In the subsequent sections, I shall discuss all of the AT&T modem lights one by one along with relevant helpful information.

1. Power Light

Power Light on AT&T Modem
  • Meaning: The modem is powered on
  • Ideal Light Color: Solid Green

Different States of Power Light and Their Meanings:

  • Solid Green: Modem is in operational mode and is powered on
  • Solid Red: Modem has malfunctioned
  • Flashing Red: Self-test is in progress
  • Light off: The modem is off

Steps to Fix if Power Light is in trouble:

  1. Try power cycling the device
  2. Unplug the device from the power source.
  3. Wait for some time
  4. Restart again.

2. Ethernet Light

Ethernet Light on AT&T Modem
  • Meaning: The device is connected by ethernet
  • Ideal Light Color: Solid Green

Different States of Ethernet Light and Their Meanings:

  • Solid Green: The device is connected by ethernet to the modem.
  • Flashing Green: Traffic between the connected device and modem.
  • Flashing Green with DSL light: Hardware issue detected.
  • Light off: The modem is off.

Steps to Fix if Ethernet Light is in trouble:

  1. Begin with restarting the device. If this did not help,
  2. You should check for the software update.
  3. If you find any, install it.

3. DSL Light

DSL Light on AT&T Modem
  • Meaning: DSL signal is detected
  • Ideal Light Color: Solid Green

Different States of DSL Light and Their Meanings:

  • Solid Green: Modem is connected to the DSL
  • Flashing Green: Modem is attempting to sync with the DSL
  • Flashing Red: No DSL signal is detected
  • Flashing Green/ Red: Modem failed to sync with DSL three times
  • Flashing Red with ethernet status light: Hardware failure detected
  • Solid Red: Hardware failure detected
  • Light off: The modem is off

Steps to Fix if the DSL Light is in trouble:

  1. When the issue is in hardware, restarting might not help.
  2. You need to consult a technician for help in that case.

4. Internet Light

Internet Light on AT&T Modem
  • Meaning: The device is connected to the AT&T internet
  • Ideal Light Color: Solid Green

Different States of Internet Light and Their Meanings:

  • Solid Green: Modem is connected to the internet
  • Flashing Green: Modem is attempting to connect to the internet
  • Solid Red: Modem cannot connect to the internet
  • Light off: The modem is off

Steps to Fix if Internet Light is in trouble:

  1. Check with your local operator if the issue lies from their end.
  2. If not, restart the device and check for internet status again.

5. Activity Light

Activity Light on AT&T Modem
  • Meaning: Inbound internet traffic
  • Ideal Light Color: Flashing Green

Different States of Activity Light and Their Meanings:

  • Flashing Green: Inbound internet traffic
  • Light off: The modem is off or no inbound internet traffic

Steps to Fix if Activity Light is in trouble:

  1. This will be fixed most probably by rebooting the device.
  2. Unplug the modem from the power source.
  3. Wait for a few minutes.
  4. Restart it again.

ATT Router Symbols

Light NameStateMeaning
PowerSolid GreenPower is on
Light OffThe gateway is off, or malfunctioning
Flashing GreenThe gateway is trying to start
Solid RedPower on/self-test failed, or gateway has malfunctioned
EthernetSolid GreenA device is connected to the ethernet port
Flashing GreenTraffic between connected device and router
BatterySolid GreenBattery is installed, but the gateway is not
currently using the battery power
Flashing GreenThe Battery is charging
Flashing AmberThe gateway is running on the battery power
WiFiSolid GreenA device is connected to the gateway using the
wireless connection
Flashing GreenData traffic is passing from the device using a
wireless connection
Phone 1Solid GreenPhone is connected and registered
Flashing GreenAssociated phone line is active
Phone 2Not used or connected
USBNot used
Broadband 1Solid GreenThe gateway is connected to the network
Flashing GreenThe gateway is trying to connect to the network
Flashing Green and RedThe gateway tried to connect to the network
for more than three minutes
Flashing RedThe gateway cannot connect to the internet.
Broadband 2Not in use
ServiceSolid GreenThe broadband connection is active
Fast Flashing GreenThe gateway is trying to obtain IP address
Slow Flashing GreenAuthentication failure
Solid RedInternet service authentication failed

AT&T Router Lights: Meanings, States, Fixes

Now, I will talk about all AT&T router lights one by one along with relevant helpful information.

1. Power Light

Power Light on AT&T Router or Gateway
  • Meaning: The gateway is powered on
  • Ideal Light Color: Solid Green

Different States of Power Light and Their Meanings:

  • Solid Green: Gateway is in operational mode and is powered on
  • Solid Red: Gateway has malfunctioned
  • Flashing Green: Gateway is trying to start
  • Light off: The gateway is off

Steps to Fix if Power Light is in trouble:

  1. Try restarting/power cycling.
  2. Disconnect the power supply.
  3. Unplug the device.
  4. Wait for a few minutes.
  5. Restart the device.
  6. You can also factory reset the AT&T router if restarting did not help.

2. Ethernet Light

Ethernet Light on AT&T Router or Gateway
  • Meaning: There is an active ethernet connection
  • Ideal Light Color: Solid Green

Different States of Ethernet Light and Their Meanings:

  • Solid Green: The device is connected to the ethernet port
  • Flashing Green: Data traffic is passing from the connected device to the ethernet port

Steps to Fix if Ethernet Light is in trouble:

  1. Check ethernet cable
  2. Check that the ethernet cable is properly plugged into both the device and modem port.
  3. Try plugging the cable into a different port.
  4. You can use a different ethernet cable in case the first one is faulty.

3. Battery Light

Battery Light on AT&T Router or Gateway
  • Meaning: The battery is installed
  • Ideal Light Color: Solid Green

Different States of Battery Light and Their Meanings:

  • Solid Green: Battery is installed, but the gateway is not using the battery power
  • Flashing Green: The battery is charging
  • Flashing Amber: The gateway is using the battery power

Steps to Fix if Battery Light is in trouble:

  1. Switch off the device.
  2. Remove the plug from the power source.
  3. Wait for a few minutes.
  4. Plug the device again and restart it.

4. WiFi Light

WiFi Light on AT&T Router or Gateway
  • Meaning: The device is connected
  • Ideal Light Color: Solid Green

Different States of WiFi Light and Their Meanings:

  • Solid Green: A device is connected using a wireless connection
  • Flashing Green: Data traffic is passing from the connected device using a wireless connection

Steps to Fix if WiFi Light is in trouble:

  1. Reboot the device
  2. Restart again to check if the issue is gone.

5. Service Light

Service Light on AT&T Router or Gateway
  • Meaning: The service light on ATT router indicates it has obtained an IP address.
  • Ideal Light Color: Solid Green

Different States of Service Light and Their Meanings:

  • Solid Green: IP address has been obtained
  • Solid or Blinking Red: The blinking red light on the AT&T router indicates that the internet service authentication has failed
  • Fast Flashing Green: The gateway is trying to obtain the IP address
  • Slow Flashing Green: The gateway is configured incorrectly.

Steps to Fix if Service Light is in trouble:

  1. Try restarting the device.
  2. Disconnect the power supply.
  3. Unplug the device.
  4. Wait for a few minutes.
  5. Restart the device.
  6. You can also factory reset the device if restarting does not help.

Note: If your device often faces lights flashing/connectivity issues, consider getting your own router for A&T internet. It would work much better than ISP-rented equipment.

Frequently Asked Questions

What colour should the light be on AT&T Modem?

Your AT&T modem should have a Solid Green light if it is connected to the internet and working properly. If the modem is showing a Flashing Green or Red light, this means the device is having a problem connecting to the internet.

How do I know if my ATT modem is working?

A Solid Green light on the AT&T modem means the device is working properly. In that case, you will be able to use the internet without any disruption.

What could be the reason behind AT&T modem all lights flashing red?

An interrupted firmware update, a glitch in a network connection, or hardware failure can make ATT modem lights flash red light. Try the fixes mentioned in the article above.

How do I troubleshoot my ATT modem?

Troubleshooting AT&T modem is not a big problem. To begin with, you must restart the device. Most of the time, the issue is fixed in this step only. If you still are facing difficulties connecting to the internet, you need to check for software and hardware issues as well. And lastly, contact a technician if nothing works.

Conclusion

By now, you must have a clear understanding of AT&T Uverse modem lights. Your device must show a Solid Green colour when working properly. Any other colour might signify there is some issue, and you must fix it. Hopefully, you now have an idea of the lights and how to troubleshoot them.