nbn® Connection Box Indicator Lights

The nbn® connection box (formerly called the Network Termination Device or connection box) is the point where the nbn® network connects to your home. Understanding what the various indicator lights mean can help you troubleshoot connection issues and determine when you might need technical support.

This guide explains what each light on your nbn® connection box means and what actions you should take based on their status.

Sky Muster

State	Meaning
No Light (Off)	No AC power supply. Please ensure the nbn® connection box has power.
Solid White	Initial power-up. Wait for nbn® connection box to finish powering up.
Flashing White	nbn® connection box is attempting to connect to the network. Wait for the connection attempt to finish.
Solid Blue	nbn® connection box is online.
Flashing Blue	Indicates network activity on a successful connection.
Solid Yellow	nbn® connection box is in sleep mode.
Flashing Yellow	nbn® connection box is in installation mode. Wait for installation to complete.
Solid Red	The Nbn® connection box needs to be rebooted. For a quick reboot, simply use a pen or paper clip to press and release the RESET button on the back of the nbn® connection box.
Flashing Red	May indicate a fault.

Fixed Wireless

Light	State	Meaning
Power	No Light (Off)	No power supply. All other lights will be off if the nbn® connection box has no power.
	Solid Red	nbn® connection box is operating on backup battery power and power is low (if a battery has been fitted).
	Solid Green	nbn® connection box has power.
	Flashing Green	nbn® connection box is operating on backup battery power (if a battery has been fitted).
Status	No Light	nbn® connection box has no power or is in an unexpected state.
	Solid Red	A system fault is detected.
	Flashing Yellow	nbn® connection box is booting up/initialising.
	Solid Green	nbn® connection box is in test mode.
	Flashing Green	nbn® connection box is operating normally.
Outdoor Unit (ODU)	No Light	nbn® connection box has no power or is in an unexpected state.
	Solid Red	nbn® connection box is offline.
	Flashing Red	An error is detected.
	Solid Green	nbn® connection box is online.
	Flashing Green	Network activity.
Signal Strength	No Light	nbn® connection box has no power or is offline.
	Solid Red	Low signal strength (this is not necessarily a service fault as factors such as local weather can impact signal strength).
	Solid Yellow	Medium signal strength.
	Solid Green	High signal strength.

FTTC

Light	State	Meaning
LAN	No Light (Off)	nbn® NCD has no power or is not connected to a modem/router.
	Solid Blue	Successful connection between nbn® NCD and modem/router. Flashing indicates local network activity.
	Solid Amber	Successful connection between nbn® NCD and modem/router. Flashing indicates local network activity.
DSL	No Light	nbn® NCD has no power or is not communicating with the nbn®.
	Solid Blue	nbn® NCD is successfully communicating with the nbn®.
Connection	No Light	nbn® NCD has no power.
	Solid Blue	Successful reverse power to nbn® equipment outside the premises.
	Solid Red	Issue with reverse power.
Power	No Light	nbn® NCD has no power.
	Solid Blue	nbn® NCD has power.

FTTP

Light	State	Meaning
Power	No Light (Off)	No power supply. Please note that all other lights will be off if the nbn® connection box has no power.
	Solid Red	nbn® connection box is operating on backup battery power from the Power Supply unit.
	Solid Green	nbn® connection box has power. Sometimes the light may look more orange/yellow than green – this is fine.
Optical	No Light	nbn® connection box is disabled.
	Solid Red	No connection to the network.
	Solid Green	Connected successfully to the network. This light will flash during data transfer.
Alarm	No Light	nbn® connection box is working, but no devices are connected.
	Solid Red	Issue detected.
	Solid Green	nbn® connection box is working with no issues detected.
UNI-D 1/2/3/4	No Light	Nothing is plugged into this port. Only one UNI-D port is active for a single nbn® service – typically port UNI-D1.
	Solid Yellow	A device capable of up to 1000Mbps is plugged in. This light will flash during data transfer.
	Solid Green	A device capable of up to 10/100Mbps is plugged in. This light will flash during data transfer.
UNI-V 1/2	No Light	There is no nbn® Fibre Phone service, or it’s not currently being used.
	Solid Green	One or more nbn® Fibre phones are off the hook (typically because they are being used).
	Flashing Green	One or more nbn® Fibre phones have been off the hook for more than an hour. If no one is on a long phone call, check that your handsets are not engaged and have been returned to the hook or cradle.
Update	No Light	Normal, no action required.
	Solid Red	nbn® connection box has failed to download an update.
	Solid Green	nbn® connection box is currently downloading an update with no issues.

HFC

Light	State	Meaning
Power	No Light (Off)	nbn® connection box has no power.
	Solid Green	nbn® connection box has power.
Downstream	No Light	nbn® connection box has no power.
	Solid Green	Successful downstream connection.
	Flashing Green	Searching for downstream connection. If ONLINE light is on, firmware upgrade in progress.
Upstream	No Light	Still searching for downstream connection, or nbn® connection box has no power.
	Solid Green	Successful downstream connection.
	Flashing Green	Downstream connection found; searching for upstream connection. If ONLINE light is on, firmware upgrade in progress.
Online	No Light	nbn® connection box is offline or has no power.
	Solid Green	nbn® connection box is online and browsing should be possible.
	Flashing Green	Downstream and upstream connection found; retrieving setup information from nbn®.
On the back	Solid Green	Cable connection detected. If this light is off, try another CAT5e or CAT6 Ethernet cable.
	Solid Yellow	Old CAT5 Ethernet cable is in use -this may not allow throughput of the full speed of your nbn® HFC service.

Beyond the Connection Box: Optimising Your Home Setup

While the indicator lights on your nbn® connection box can help identify issues with your connection to the nbn® network, many internet performance problems stem from what happens after the signal reaches your home.

Router Placement and Performance

After the signal passes through your nbn® connection box, it typically connects to your router, which distributes the internet throughout your home. Strategic router placement eliminates dead zones and maximises coverage:

– Position your router centrally in your home, away from concrete walls, metal objects, and electronic devices that can cause interference
– Elevate your router off the floor, ideally at chest height or higher

– Keep antennas vertical if your router has external antennas
– Avoid enclosures that can block signals, such as cabinets or entertainment units

Equipment Age Considerations

Even with a perfectly functioning nbn® connection box showing all green lights:

– Router age matters significantly. If your router is more than 5 years old, it likely uses outdated technology that cannot support modern internet speeds and security protocols, regardless of your nbn® plan.
– Wi-Fi standards affect performance. Newer Wi-Fi standards (Wi-Fi 5/6/6E) offer significantly better performance than older generations, but only when both your router and devices support them.

Connection Type Awareness

For reliable performance with demanding applications:

– Consider wired connections for stationary devices like smart TVs, desktop computers, and gaming consoles. While Wi-Fi offers convenience, a direct ethernet connection provides superior stability.
– For larger homes, traditional Wi-Fi extenders have significant limitations. Mesh systems provide more seamless coverage by creating a unified network throughout your home.

Troubleshooting Common Issues

If you’re experiencing internet connectivity problems, these steps can help you diagnose and potentially resolve the issue:

No Lights on the Connection Box

1. Ensure the power adapter is securely connected to both the connection box and the power outlet
2. Try a different power outlet
3. Check if there’s a power outage in your area
4. If steps 1-3 don’t resolve the issue, contact your provider

All Lights Are Green But No Internet

If all lights on your nbn® connection box are green but you still can’t access the internet, the issue likely lies with your router or internal network:

1. Restart your router by turning it off for 30 seconds, then back on
2. Check the connection between your router and the nbn® connection box
3. Try connecting a computer directly to your nbn® connection box with an ethernet cable
4. If direct connection works, the issue is with your router
5. Consider your router’s age and placement. Outdated equipment or poor positioning can cause connectivity issues even when your nbn® connection is working perfectly

Intermittent Connection

If your internet connection is dropping frequently:

1. Check all cable connections to ensure they’re secure
2. Restart both your nbn® connection box and router
3. Check for interference sources near your equipment
4. Test your connection using a wired ethernet connection. If wired works reliably but Wi-Fi doesn’t, the issue is with your Wi-Fi distribution rather than your nbn® connection
5. For larger homes, consider whether your Wi-Fi coverage solution is adequate. Traditional Wi-Fi extenders have significant limitations, while mesh systems provide more seamless coverage

When to Contact Support

You should contact your internet service provider when:

• Your connection box shows red lights or no lights despite checking power and connections
• The online or DSL/sync light remains off or flashing for an extended period
• You’ve performed all troubleshooting steps and still can’t connect to the internet
• Your connection is consistently slower than expected or frequently drops

Key Points to Remember

When using the indicator lights on your nbn® connection box to troubleshoot connection issues:

• Green usually means good: For most indicators, a solid green light means that aspect of your connection is functioning properly.
• Connection box vs. home network: The nbn® connection box only indicates the status of your connection to the nbn® network, not issues that might exist within your home network.
• Home setup impact: Recent research shows that 42% of nbn users haven’t updated their home setup in five years.* Your equipment configuration fundamentally shapes your internet experience, even when your connection box shows all green lights.
• Test methodically: When troubleshooting, use wired connections where possible to determine whether issues are with your nbn® connection or your Wi-Fi distribution.
• Consider equipment age: If your router is more than 5 years old, consider upgrading as it likely uses outdated technology that cannot support modern internet speeds, regardless of what your connection box lights indicate.
• Document light patterns: When contacting support, note the exact pattern of lights on your connection box to help technicians diagnose the issue more efficiently.

*nbn commissioned survey in 2025: residential consumers who use nbn as their main internet service at home (Sample size of 6,225)

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