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Internet

How to Understand the Lights on Your Purple Fibre ONT

Last reviewed 2026-05-11

The ONT is the fibre modem for Purple Fibre service. Its lights can help show whether a problem looks like power, fibre signal, internet activation, or Wi-Fi.

Before You Start

  • Look at the ONT before restarting it so you can note which lights are on, off, or unusual.
  • Light labels can vary. The most helpful ones are usually Power, PON or Optical, Alarm, and Internet.
  • Don't unplug the fibre line or open fibre equipment covers.

Steps

  1. Check whether the Power light is on and stable so you know the ONT is receiving power.
  2. Look for the fibre signal light, usually labelled PON or Optical. If it is off, red, or clearly abnormal, the issue may be fibre-signal related rather than a simple Wi-Fi issue.
  3. Check for an Alarm light. If an alarm is showing, reach out rather than continuing extended troubleshooting.
  4. Check the Internet light to see whether the ONT appears to be online after the fibre signal comes up.
  5. If the ONT lights look normal and only Wi-Fi devices are affected, move to Wi-Fi troubleshooting instead of assuming the fibre line is down.

Frequently asked questions

Which ONT lights matter most?
Start with Power, PON or Optical, Alarm, and Internet. Those lights usually show whether the ONT is powered, seeing fibre signal, and online.
Can I fix a red or missing PON light myself?
A red or missing PON light often points to a signal or provisioning issue. Reach out and we'll help from there.
When should I reach out?
If things still aren't behaving, reach out and we'll help from there.

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