nbn HFC Connection Box Status Lights
Checking the status lights on your nbn Connection Box (NCB) for nbn HFC can be useful for troubleshooting.
Select one of the links below to jump to a query:
Arris CM3500 nbn HFC Connection Box Status lights
This model was supplied from 19 March 2025 onwards.
On the back
| Light | State | Meaning | |
| 2.5 G LINK | Off | Nothing is plugged into the 2.5G port. | |
| Green | A device is plugged in with a CAT5e or CAT6 Ethernet cable. | ||
| Yellow | A device is plugged in with an older CAT5 Ethernet cable, which may not support the full speed of your nbn HFC plan. We recommend switching to a CAT5e ot CAT6 Ethernet cable. | ||
On the front
| Light | State | Meaning | |
| POWER | Off | No power. | |
| Green | Your NCB has power. | ||
| DOWNSTREAM | Off | Your NCB is still searching for a connection, or has no power. | |
| Green | Your NCB can download data. | ||
| Flashing | A firmware upgrade is in progress - this should take 10 minutes or less. | ||
| UPSTREAM | Off | Your NCB is still searching for a connection, or has no power. | |
| Green | Your NCB can upload data. | ||
| Flashing | A firmware upgrade is in progress - this should take 10 minutes or less. | ||
| ONLINE | Off | No connection to the network. | |
| Green | Your nbn connection is working as expected. | ||
Arris CM8200 nbn HFC Connection Box Status lights
This model was supplied before 19 March 2025.
On the back
The UNI-D1 port on the back of the Connection Box has LINK lights to indicate cable connection to a computer or router.
- Green: Cable connection detected. If this light is off, try another CAT5e or CAT6 Ethernet cable.
- Yellow: Old CAT5 Ethernet cable is in use - this may not allow throughput of the full speed of your nbn HFC service.
On the front
- Note that ONLINE, DOWNSTREAM and UPSTREAM lights will all FLASH briefly when the Connection Box is powered on. This is a self-test and no action is needed, just wait for the Connection Box to finish booting up.
- If both UPSTREAM and DOWNSTREAM lights are FLASHING but ONLINE light is OFF, there is no connection to the nbn. Please call us on 13 22 58 for assistance.
- If both UPSTREAM and DOWNSTREAM lights are FLASHING and ONLINE light is ON, a firmware update is in progress. No action is needed - simply wait for the update to complete.
| Light | State | Meaning | |
| POWER | Off | Connection Box has no power. | |
| Green | Connection Box has power. | ||
| DOWNSTREAM | Off | Connection Box has no power. | |
| Green | Successful downstream connection. | ||
| Flashing | Searching for downstream connection. If ONLINE light is on, firmware upgrade in progress. | ||
| UPSTREAM | Off | Still searching for downstream connection, or Connection Box has no power. | |
| Green | Successful upstream connection. | ||
| Flashing | Downstream connection found; searching for upstream connection. If ONLINE light is on, firmware upgrade in progress. | ||
| ONLINE | Off | Connection Box is offline or has no power. | |
| Green | Connection Box is online and browsing should be possible. | ||
| Flashing | Downstream and upstream connection found; retrieving setup information from nbn. | ||
