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FTTP box lights: what each one means
Fibre runs the whole way to your wall. Inside you have an nbn connection box with a row of lights down one side, and your own router plugs into one of its UNI-D ports. Below is every indicator on the nbn connection box with nbn's own documented meaning, and the action that goes with it.
Last reviewed: 15 August 2026 · by Alien IT Solutions
What you are looking at
Fibre runs the whole way to your wall. Inside you have an nbn connection box with a row of lights down one side, and your own router plugs into one of its UNI-D ports.
Two generations of FTTP box are in the field and their alarm lights do not mean the same thing. On the current boxes documented by nbn, alarm off is normal. On some older units the alarm indicator is green when working normally and off when the box is powered but has nothing connected. If your box does not match the table above, read the label on the front and quote the model number to your provider rather than guessing.
Every light on the nbn connection box, and what it means
This table is nbn's own documentation for this equipment, not one provider's summary of it. Where your provider's guide says something different about your specific hardware, follow theirs, because they know which model they sent you.
| Light | What you see | What it means | What to do |
|---|---|---|---|
| Power | Off | There is no power to your nbn connection box. | Check the power supply is plugged in, switched on at the wall, and connected to the box. If there is still no power light, contact your provider. |
| Green, slow flashing | The box is starting up. | Wait. It should settle to solid green shortly. | |
| Green, fast flashing | The box is being upgraded or is receiving updates. | Wait. Do not switch it off partway through an update. | |
| Green, solid | Power is normal and the box is ready. | Nothing to do. | |
| Optical | Off | Your connection box is not connected to the nbn network. | This is a network side problem, not a setting you can change. Contact your provider and report it as no optical light. |
| Green, steady | The box is connected to the nbn network and can receive data. | Nothing to do. | |
| Green, slow flashing | There is activity on the connection and data is moving. | Nothing to do. This is normal, not a fault. | |
| Red | Your connection box has lost its connection to the nbn network. | This is the one that matters. It is a network side fault. Contact your provider, tell them the optical light is red, and ask them to raise it with nbn. | |
| Alarm | Off | The box is operating normally. | Nothing to do. |
| Red | The box has a fault and is not working normally. | Contact your provider and quote the alarm light. The box is nbn equipment, so replacing it is their job to arrange. | |
| UNI-D (the port your router is plugged into) | Off | No active service on that port right now. | If your router is plugged in and switched on, try the next UNI-D port, then tell your provider which ports you have tried. |
| Orange | The device plugged in is running at 1Gbps Ethernet. | Nothing to do. This is what you want on a fast plan. | |
| Green | The device plugged in is running at 10 or 100Mbps Ethernet. | Worth knowing. Green here means the link between your router and the nbn box negotiated 100Mbps or slower, which caps your service below a 250Mbps or 1000Mbps plan no matter what you pay. Try a different Ethernet cable, ideally one marked Cat5e or Cat6, and a different port on your router. | |
| Voice (UNI-V), if you have a phone service on the box | Off | No active phone service on that port. | Nothing to do. |
| Green | A telephone is off the hook and in use. | Nothing to do if someone is on a call. | |
| Green, flashing | A telephone has been off the hook for more than an hour. | Walk around and check every handset in the house, including cordless ones sitting crooked on the base. A handset left off the hook is a real fault that looks like a line problem. |
Now turn the light into a diagnosis
A light tells you the state. It does not tell you the cause, and the cause is what gets it fixed. Pick the pattern that matches what your connection has actually been doing, and you will land on the FTTP answer for it.
- The internet drops out at the same time every dayIs it predictable, for example most evenings, or always around the same hour?
- The internet drops out when it rainsDoes it get worse in rain, or in the day or two after rain?
- The internet drops out then comes back on its ownDoes it come back without you touching anything, after seconds or minutes?
- The internet drops out every few minutesIs it constant, several times an hour, all day?
- The internet has been dead since a particular dayDid it stop on a particular day and never come back?
- The internet is slow but never actually drops outDoes it stay connected but run far below what you pay for?
Before you touch anything
- Do not go up a ladder or onto a roof. That includes fixed wireless antennas and dishes. nbn's own fixed wireless guide tells you to contact your provider rather than touch an outdoor unit mounted more than 2 metres off the ground. There is nothing you can fix up there that is worth a fall.
- Do not open the nbn connection box, and do not touch the pit or the lead-in cable. That equipment belongs to nbn, not to you or your provider. Fibre terminations carry laser light that you cannot see and should not look into. Opening it can also end your service and leave you liable for the repair.
- Leave the backup battery alone beyond what your provider's own script tells you. If you have the optional Power Supply with Battery Backup, follow your provider's instructions for it and nothing more.
- Burning smell, scorch marks, or a modem too hot to touch: stop. Switch it off at the wall, unplug it, and do not plug it back in. Tell your provider it needs replacing. There is no troubleshooting step that comes before this.
Where this comes from
Every light state and every figure on this page comes from the sources below, each checked on 15 August 2026. Where a provider's guide disagrees with nbn's, the provider is describing their own hardware and you should follow theirs.
While you are on the phone to them anyway
Most people only look hard at their telco account when something has gone wrong. Since you are already dealing with them, send the bill over. The audit is free, and we will tell you plainly where you are overpaying and what is worth challenging.
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